diff --git a/python/ray/rllib/common.py b/python/ray/rllib/common.py
index de0c57d0a..c30a8267b 100644
--- a/python/ray/rllib/common.py
+++ b/python/ray/rllib/common.py
@@ -8,6 +8,7 @@ import sys
 import tempfile
 import uuid
 import smart_open
+
 if sys.version_info[0] == 2:
     import cStringIO as StringIO
 elif sys.version_info[0] == 3:
@@ -60,9 +61,9 @@ class Algorithm(object):
     you should create a new algorithm instance for each training session.
 
     Attributes:
-      env_name (str): Name of the OpenAI gym environment to train against.
-      config (obj): Algorithm-specific configuration data.
-      logdir (str): Directory in which training outputs should be placed.
+        env_name (str): Name of the OpenAI gym environment to train against.
+        config (obj): Algorithm-specific configuration data.
+        logdir (str): Directory in which training outputs should be placed.
 
     TODO(ekl): support checkpoint / restore of training state.
     """
@@ -71,11 +72,11 @@ class Algorithm(object):
         """Initialize an RLLib algorithm.
 
         Args:
-          env_name (str): The name of the OpenAI gym environment to use.
-          config (obj): Algorithm-specific configuration data.
-          upload_dir (str): Root directory into which the output directory
-            should be placed. Can be local like file:///tmp/ray/ or on S3
-            like s3://bucketname/.
+            env_name (str): The name of the OpenAI gym environment to use.
+            config (obj): Algorithm-specific configuration data.
+            upload_dir (str): Root directory into which the output directory
+                should be placed. Can be local like file:///tmp/ray/ or on S3
+                like s3://bucketname/.
         """
         upload_dir = "file:///tmp/ray" if upload_dir is None else upload_dir
         self.experiment_id = uuid.uuid4()
@@ -88,8 +89,8 @@ class Algorithm(object):
             self.__class__.__name__,
             datetime.today().strftime("%Y-%m-%d_%H-%M-%S"))
         if upload_dir.startswith("file"):
-            self.logdir = "file://" + tempfile.mkdtemp(prefix=prefix,
-                                                       dir="/tmp/ray")
+            self.logdir = "file://" + tempfile.mkdtemp(
+                prefix=prefix, dir="/tmp/ray")
         else:
             self.logdir = os.path.join(upload_dir, prefix)
         log_path = os.path.join(self.logdir, "config.json")
@@ -103,7 +104,7 @@ class Algorithm(object):
         """Runs one logical iteration of training.
 
         Returns:
-          A TrainingResult that describes training progress.
+            A TrainingResult that describes training progress.
         """
 
         raise NotImplementedError
diff --git a/python/ray/rllib/evolution_strategies/evolution_strategies.py b/python/ray/rllib/evolution_strategies/evolution_strategies.py
index 21062dc19..537338036 100644
--- a/python/ray/rllib/evolution_strategies/evolution_strategies.py
+++ b/python/ray/rllib/evolution_strategies/evolution_strategies.py
@@ -73,15 +73,15 @@ class Worker(object):
 
         self.env = gym.make(env_name)
         self.sess = utils.make_session(single_threaded=True)
-        self.policy = policies.MujocoPolicy(self.env.observation_space,
-                                            self.env.action_space,
-                                            **policy_params)
+        self.policy = policies.GenericPolicy(
+            self.env.observation_space, self.env.action_space, **policy_params)
         tf_util.initialize()
 
         self.rs = np.random.RandomState()
 
-        assert self.policy.needs_ob_stat == (self.config["calc_obstat_prob"] !=
-                                             0)
+        assert (
+            self.policy.needs_ob_stat ==
+            (self.config["calc_obstat_prob"] != 0))
 
     def rollout_and_update_ob_stat(self, timestep_limit, task_ob_stat):
         if (self.policy.needs_ob_stat and
@@ -109,15 +109,15 @@ class Worker(object):
 
         noise_inds, returns, sign_returns, lengths = [], [], [], []
         # We set eps=0 because we're incrementing only.
-        task_ob_stat = utils.RunningStat(self.env.observation_space.shape,
-                                         eps=0)
+        task_ob_stat = utils.RunningStat(
+            self.env.observation_space.shape, eps=0)
 
         # Perform some rollouts with noise.
         task_tstart = time.time()
         while (len(noise_inds) == 0 or
                time.time() - task_tstart < self.min_task_runtime):
-            noise_idx = self.noise.sample_index(self.rs,
-                                                self.policy.num_params)
+            noise_idx = self.noise.sample_index(
+                self.rs, self.policy.num_params)
             perturbation = self.config["noise_stdev"] * self.noise.get(
                 noise_idx, self.policy.num_params)
 
@@ -133,8 +133,8 @@ class Worker(object):
 
             noise_inds.append(noise_idx)
             returns.append([rews_pos.sum(), rews_neg.sum()])
-            sign_returns.append([np.sign(rews_pos).sum(),
-                                 np.sign(rews_neg).sum()])
+            sign_returns.append(
+                [np.sign(rews_pos).sum(), np.sign(rews_neg).sum()])
             lengths.append([len_pos, len_neg])
 
             return Result(
@@ -157,13 +157,17 @@ class EvolutionStrategies(Algorithm):
         Algorithm.__init__(self, env_name, config, upload_dir=upload_dir)
 
         policy_params = {
-            "ac_bins": "continuous:",
-            "ac_noise_std": 0.01,
-            "nonlin_type": "tanh",
-            "hidden_dims": [256, 256],
-            "connection_type": "ff"
+            "ac_noise_std": 0.01
         }
 
+        env = gym.make(env_name)
+        utils.make_session(single_threaded=False)
+        self.policy = policies.GenericPolicy(
+            env.observation_space, env.action_space, **policy_params)
+        tf_util.initialize()
+        self.optimizer = optimizers.Adam(self.policy, config["stepsize"])
+        self.ob_stat = utils.RunningStat(env.observation_space.shape, eps=1e-2)
+
         # Create the shared noise table.
         print("Creating shared noise table.")
         noise_id = create_shared_noise.remote()
@@ -171,17 +175,9 @@ class EvolutionStrategies(Algorithm):
 
         # Create the actors.
         print("Creating actors.")
-        self.workers = [Worker.remote(config, policy_params, env_name,
-                                      noise_id)
-                        for _ in range(config["num_workers"])]
-
-        env = gym.make(env_name)
-        utils.make_session(single_threaded=False)
-        self.policy = policies.MujocoPolicy(
-            env.observation_space, env.action_space, **policy_params)
-        tf_util.initialize()
-        self.optimizer = optimizers.Adam(self.policy, config["stepsize"])
-        self.ob_stat = utils.RunningStat(env.observation_space.shape, eps=1e-2)
+        self.workers = [
+            Worker.remote(config, policy_params, env_name, noise_id)
+            for _ in range(config["num_workers"])]
 
         self.episodes_so_far = 0
         self.timesteps_so_far = 0
@@ -241,13 +237,13 @@ class EvolutionStrategies(Algorithm):
             curr_task_results.append(result)
             # Update ob stats.
             if self.policy.needs_ob_stat and result.ob_count > 0:
-                self.ob_stat.increment(result.ob_sum, result.ob_sumsq,
-                                       result.ob_count)
+                self.ob_stat.increment(
+                    result.ob_sum, result.ob_sumsq, result.ob_count)
                 ob_count_this_batch += result.ob_count
 
         # Assemble the results.
-        noise_inds_n = np.concatenate([r.noise_inds_n for
-                                       r in curr_task_results])
+        noise_inds_n = np.concatenate(
+            [r.noise_inds_n for r in curr_task_results])
         returns_n2 = np.concatenate([r.returns_n2 for r in curr_task_results])
         lengths_n2 = np.concatenate([r.lengths_n2 for r in curr_task_results])
         assert (noise_inds_n.shape[0] == returns_n2.shape[0] ==
@@ -265,9 +261,10 @@ class EvolutionStrategies(Algorithm):
              for idx in noise_inds_n),
             batch_size=500)
         g /= returns_n2.size
-        assert (g.shape == (self.policy.num_params,) and
-                g.dtype == np.float32 and
-                count == len(noise_inds_n))
+        assert (
+            g.shape == (self.policy.num_params,) and
+            g.dtype == np.float32 and
+            count == len(noise_inds_n))
         update_ratio = self.optimizer.update(-g + config["l2coeff"] * theta)
 
         # Update ob stat (we're never running the policy in the master, but we
diff --git a/python/ray/rllib/evolution_strategies/policies.py b/python/ray/rllib/evolution_strategies/policies.py
index 20273130f..db6c2716e 100644
--- a/python/ray/rllib/evolution_strategies/policies.py
+++ b/python/ray/rllib/evolution_strategies/policies.py
@@ -8,11 +8,13 @@ from __future__ import print_function
 import logging
 import pickle
 
+import gym.spaces
 import h5py
 import numpy as np
 import tensorflow as tf
 
 from ray.rllib.evolution_strategies import tf_util as U
+from ray.rllib.models import ModelCatalog
 
 logger = logging.getLogger(__name__)
 
@@ -137,24 +139,10 @@ def bins(x, dim, num_bins, name):
     return tf.argmax(scores_nab, 2)
 
 
-class MujocoPolicy(Policy):
-    def _initialize(self, ob_space, ac_space, ac_bins, ac_noise_std,
-                    nonlin_type, hidden_dims, connection_type):
+class GenericPolicy(Policy):
+    def _initialize(self, ob_space, ac_space, ac_noise_std):
         self.ac_space = ac_space
-        self.ac_bins = ac_bins
         self.ac_noise_std = ac_noise_std
-        self.hidden_dims = hidden_dims
-        self.connection_type = connection_type
-
-        assert len(ob_space.shape) == len(self.ac_space.shape) == 1
-        assert (np.all(np.isfinite(self.ac_space.low)) and
-                np.all(np.isfinite(self.ac_space.high))), ("Action bounds "
-                                                           "required")
-
-        self.nonlin = {'tanh': tf.tanh,
-                       'relu': tf.nn.relu,
-                       'lrelu': U.lrelu,
-                       'elu': tf.nn.elu}[nonlin_type]
 
         with tf.variable_scope(type(self).__name__) as scope:
             # Observation normalization.
@@ -171,72 +159,24 @@ class MujocoPolicy(Policy):
                 tf.assign(ob_std, in_std),
             ])
 
+            inputs = tf.placeholder(tf.float32, [None] + list(ob_space.shape))
+
+            # TODO(ekl): we should do clipping in a standard RLlib preprocessor
+            clipped_inputs = tf.clip_by_value(
+                (inputs - ob_mean) / ob_std, -5.0, 5.0)
+
             # Policy network.
-            o = tf.placeholder(tf.float32, [None] + list(ob_space.shape))
-            a = self._make_net(tf.clip_by_value((o - ob_mean) / ob_std,
-                                                -5.0, 5.0))
-            self._act = U.function([o], a)
+            dist_class, dist_dim = ModelCatalog.get_action_dist(
+                self.ac_space, dist_type='deterministic')
+            model = ModelCatalog.get_model(clipped_inputs, dist_dim)
+            dist = dist_class(model.outputs)
+            self._act = U.function([inputs], dist.sample())
         return scope
 
-    def _make_net(self, o):
-        # Process observation.
-        if self.connection_type == 'ff':
-            x = o
-            for ilayer, hd in enumerate(self.hidden_dims):
-                x = self.nonlin(U.dense(x, hd, 'l{}'.format(ilayer),
-                                        U.normc_initializer(1.0)))
-        else:
-            raise NotImplementedError(self.connection_type)
-
-        # Map to action.
-        adim = self.ac_space.shape[0]
-        ahigh = self.ac_space.high
-        alow = self.ac_space.low
-        assert isinstance(self.ac_bins, str)
-        ac_bin_mode, ac_bin_arg = self.ac_bins.split(':')
-
-        if ac_bin_mode == 'uniform':
-            # Uniformly spaced bins, from ac_space.low to ac_space.high.
-            num_ac_bins = int(ac_bin_arg)
-            aidx_na = bins(x, adim, num_ac_bins, 'out')
-            ac_range_1a = (ahigh - alow)[None, :]
-            a = (1. / (num_ac_bins - 1.) * tf.to_float(aidx_na) * ac_range_1a +
-                 alow[None, :])
-
-        elif ac_bin_mode == 'custom':
-            # Custom bins specified as a list of values from -1 to 1.
-            # The bins are rescaled to ac_space.low to ac_space.high.
-            acvals_k = np.array(list(map(float, ac_bin_arg.split(','))),
-                                dtype=np.float32)
-            logger.info('Custom action values: ' + ' '.join('{:.3f}'.format(x)
-                                                            for x in acvals_k))
-            assert (acvals_k.ndim == 1 and acvals_k[0] == -1 and
-                    acvals_k[-1] == 1)
-            acvals_ak = ((ahigh - alow)[:, None] /
-                         (acvals_k[-1] - acvals_k[0]) *
-                         (acvals_k - acvals_k[0])[None, :] + alow[:, None])
-
-            aidx_na = bins(x, adim, len(acvals_k),
-                           'out')  # Values in [0, k-1].
-            a = tf.gather_nd(
-                acvals_ak,
-                tf.concat([
-                    tf.tile(np.arange(adim)[None, :, None],
-                            [tf.shape(aidx_na)[0], 1, 1]),
-                    2,
-                    tf.expand_dims(aidx_na, -1)
-                ])  # (n, a, 2)
-            )  # (n, a)
-        elif ac_bin_mode == 'continuous':
-            a = U.dense(x, adim, 'out', U.normc_initializer(0.01))
-        else:
-            raise NotImplementedError(ac_bin_mode)
-
-        return a
-
     def act(self, ob, random_stream=None):
         a = self._act(ob)
-        if random_stream is not None and self.ac_noise_std != 0:
+        if not isinstance(self.ac_space, gym.spaces.Discrete) and \
+                random_stream is not None and self.ac_noise_std != 0:
             a += random_stream.randn(*a.shape) * self.ac_noise_std
         return a
 
diff --git a/python/ray/rllib/models/README.txt b/python/ray/rllib/models/README.txt
new file mode 100644
index 000000000..d8bd20da3
--- /dev/null
+++ b/python/ray/rllib/models/README.txt
@@ -0,0 +1 @@
+Shared neural network models for RLlib.
diff --git a/python/ray/rllib/models/__init__.py b/python/ray/rllib/models/__init__.py
new file mode 100644
index 000000000..7ed71e5e6
--- /dev/null
+++ b/python/ray/rllib/models/__init__.py
@@ -0,0 +1,3 @@
+from ray.rllib.models.catalog import ModelCatalog
+
+__all__ = ["ModelCatalog"]
diff --git a/python/ray/rllib/policy_gradient/distributions.py b/python/ray/rllib/models/action_dist.py
similarity index 58%
rename from python/ray/rllib/policy_gradient/distributions.py
rename to python/ray/rllib/models/action_dist.py
index 915531c51..d1dc8687f 100644
--- a/python/ray/rllib/policy_gradient/distributions.py
+++ b/python/ray/rllib/models/action_dist.py
@@ -6,16 +6,38 @@ import tensorflow as tf
 import numpy as np
 
 
-class Categorical(object):
-    def __init__(self, logits):
-        self.logits = logits
+class ActionDistribution(object):
+    """The policy action distribution of an agent.
+
+    Args:
+      inputs (Tensor): The input vector to compute samples from.
+    """
+
+    def __init__(self, inputs):
+        self.inputs = inputs
+
+    def logp(self, x):
+        raise NotImplementedError
+
+    def kl(self, other):
+        raise NotImplementedError
+
+    def entropy(self):
+        raise NotImplementedError
+
+    def sample(self):
+        raise NotImplementedError
+
+
+class Categorical(ActionDistribution):
+    """Categorical distribution for discrete action spaces."""
 
     def logp(self, x):
         return -tf.nn.sparse_softmax_cross_entropy_with_logits(
-            logits=self.logits, labels=x)
+            logits=self.inputs, labels=x)
 
     def entropy(self):
-        a0 = self.logits - tf.reduce_max(self.logits, reduction_indices=[1],
+        a0 = self.inputs - tf.reduce_max(self.inputs, reduction_indices=[1],
                                          keep_dims=True)
         ea0 = tf.exp(a0)
         z0 = tf.reduce_sum(ea0, reduction_indices=[1], keep_dims=True)
@@ -23,9 +45,9 @@ class Categorical(object):
         return tf.reduce_sum(p0 * (tf.log(z0) - a0), reduction_indices=[1])
 
     def kl(self, other):
-        a0 = self.logits - tf.reduce_max(self.logits, reduction_indices=[1],
+        a0 = self.inputs - tf.reduce_max(self.inputs, reduction_indices=[1],
                                          keep_dims=True)
-        a1 = other.logits - tf.reduce_max(other.logits, reduction_indices=[1],
+        a1 = other.inputs - tf.reduce_max(other.inputs, reduction_indices=[1],
                                           keep_dims=True)
         ea0 = tf.exp(a0)
         ea1 = tf.exp(a1)
@@ -36,13 +58,19 @@ class Categorical(object):
                              reduction_indices=[1])
 
     def sample(self):
-        return tf.multinomial(self.logits, 1)
+        return tf.multinomial(self.inputs, 1)[0]
 
 
-class DiagGaussian(object):
-    def __init__(self, flat):
-        self.flat = flat
-        mean, logstd = tf.split(flat, 2, axis=1)
+class DiagGaussian(ActionDistribution):
+    """Action distribution where each vector element is a gaussian.
+
+    The first half of the input vector defines the gaussian means, and the
+    second half the gaussian standard deviations.
+    """
+
+    def __init__(self, inputs):
+        ActionDistribution.__init__(self, inputs)
+        mean, logstd = tf.split(inputs, 2, axis=1)
         self.mean = mean
         self.logstd = logstd
         self.std = tf.exp(logstd)
@@ -67,3 +95,13 @@ class DiagGaussian(object):
 
     def sample(self):
         return self.mean + self.std * tf.random_normal(tf.shape(self.mean))
+
+
+class Deterministic(ActionDistribution):
+    """Action distribution that returns the input values directly.
+
+    This is similar to DiagGaussian with standard deviation zero.
+    """
+
+    def sample(self):
+        return self.inputs
diff --git a/python/ray/rllib/models/catalog.py b/python/ray/rllib/models/catalog.py
new file mode 100644
index 000000000..5874c70cc
--- /dev/null
+++ b/python/ray/rllib/models/catalog.py
@@ -0,0 +1,76 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import gym
+
+from ray.rllib.models.action_dist import (
+    Categorical, Deterministic, DiagGaussian)
+from ray.rllib.models.fcnet import FullyConnectedNetwork
+from ray.rllib.models.visionnet import VisionNetwork
+
+
+class ModelCatalog(object):
+    """Registry of default models and action distributions for envs.
+
+    Example:
+        dist_class, dist_dim = ModelCatalog.get_action_dist(env.action_space)
+        model = ModelCatalog.get_model(inputs, dist_dim)
+        dist = dist_class(model.outputs)
+        action_op = dist.sample()
+    """
+
+    @staticmethod
+    def get_action_dist(action_space, dist_type=None):
+        """Returns action distribution class and size for the given action space.
+
+        Args:
+            action_space (Space): Action space of the target gym env.
+
+        Returns:
+            dist_class (ActionDistribution): Python class of the distribution.
+            dist_dim (int): The size of the input vector to the distribution.
+        """
+
+        if isinstance(action_space, gym.spaces.Box):
+            if dist_type is None:
+                return DiagGaussian, action_space.shape[0] * 2
+            elif dist_type == 'deterministic':
+                return Deterministic, action_space.shape[0]
+        elif isinstance(action_space, gym.spaces.Discrete):
+            return Categorical, action_space.n
+
+        raise NotImplementedError(
+            "Unsupported args: {} {}".format(action_space, dist_type))
+
+    @staticmethod
+    def get_model(inputs, num_outputs):
+        """Returns a suitable model conforming to given input and output specs.
+
+        Args:
+            inputs (Tensor): The input tensor to the model.
+            num_outputs (int): The size of the output vector of the model.
+
+        Returns:
+            model (Model): Neural network model.
+        """
+
+        obs_rank = len(inputs.get_shape()) - 1
+
+        if obs_rank > 1:
+            return VisionNetwork(inputs, num_outputs)
+
+        return FullyConnectedNetwork(inputs, num_outputs)
+
+    @staticmethod
+    def get_preprocessor(env_name):
+        """Returns a suitable processor for the given environment.
+
+        Args:
+            env_name (str): The name of the environment.
+
+        Returns:
+            preprocessor (Preprocessor): Preprocessor for the env observations.
+        """
+
+        raise NotImplementedError
diff --git a/python/ray/rllib/models/fcnet.py b/python/ray/rllib/models/fcnet.py
new file mode 100644
index 000000000..9237bbb67
--- /dev/null
+++ b/python/ray/rllib/models/fcnet.py
@@ -0,0 +1,37 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+import tensorflow.contrib.slim as slim
+
+import numpy as np
+
+from ray.rllib.models.model import Model
+
+
+def normc_initializer(std=1.0):
+    def _initializer(shape, dtype=None, partition_info=None):
+        out = np.random.randn(*shape).astype(np.float32)
+        out *= std / np.sqrt(np.square(out).sum(axis=0, keepdims=True))
+        return tf.constant(out)
+    return _initializer
+
+
+class FullyConnectedNetwork(Model):
+    """Generic fully connected network."""
+
+    def _init(self, inputs, num_outputs):
+        with tf.name_scope("fc_net"):
+            fc1 = slim.fully_connected(
+                inputs, 256, weights_initializer=normc_initializer(1.0),
+                activation_fn=tf.nn.tanh,
+                scope="fc1")
+            fc2 = slim.fully_connected(
+                fc1, 256, weights_initializer=normc_initializer(1.0),
+                activation_fn=tf.nn.tanh,
+                scope="fc2")
+            fc3 = slim.fully_connected(
+                fc2, num_outputs, weights_initializer=normc_initializer(0.01),
+                activation_fn=None, scope="fc3")
+            return fc3
diff --git a/python/ray/rllib/models/model.py b/python/ray/rllib/models/model.py
new file mode 100644
index 000000000..483923c82
--- /dev/null
+++ b/python/ray/rllib/models/model.py
@@ -0,0 +1,28 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+class Model(object):
+    """Defines an abstract network model for use with RLlib.
+
+    Models convert input tensors to a number of output features. These features
+    can then be interpreted by ActionDistribution classes to determine
+    e.g. agent action values.
+    """
+
+    def __init__(self, inputs, num_outputs):
+        self.inputs = inputs
+        self.outputs = self._init(inputs, num_outputs)
+
+    def _init(self):
+        """Initializes the model given self.inputs and self.num_outputs."""
+        raise NotImplementedError
+
+    def inputs(self):
+        """Returns the input placeholder for this model."""
+        return self.inputs
+
+    def outputs(self):
+        """Returns the output tensor of this model."""
+        return self.outputs
diff --git a/python/ray/rllib/models/preprocessor.py b/python/ray/rllib/models/preprocessor.py
new file mode 100644
index 000000000..a9bd75a3d
--- /dev/null
+++ b/python/ray/rllib/models/preprocessor.py
@@ -0,0 +1,14 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+
+# TODO(ekl) implement common preprocessors
+class Preprocessor(object):
+    def output_shape(self):
+        """Returns the new output shape, or None if unchanged."""
+        raise NotImplementedError
+
+    def preprocess(self, observation):
+        """Returns the preprocessed observation."""
+        raise NotImplementedError
diff --git a/python/ray/rllib/models/visionnet.py b/python/ray/rllib/models/visionnet.py
new file mode 100644
index 000000000..3d4c43132
--- /dev/null
+++ b/python/ray/rllib/models/visionnet.py
@@ -0,0 +1,22 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import tensorflow as tf
+import tensorflow.contrib.slim as slim
+
+from ray.rllib.models.model import Model
+
+
+class VisionNetwork(Model):
+    """Generic vision network."""
+
+    def _init(self, inputs, num_outputs):
+        with tf.name_scope("vision_net"):
+            conv1 = slim.conv2d(inputs, 16, [8, 8], 4, scope="conv1")
+            conv2 = slim.conv2d(conv1, 32, [4, 4], 2, scope="conv2")
+            fc1 = slim.conv2d(
+                conv2, 512, [10, 10], padding="VALID", scope="fc1")
+            fc2 = slim.conv2d(fc1, num_outputs, [1, 1], activation_fn=None,
+                              normalizer_fn=None, scope="fc2")
+            return tf.squeeze(fc2, [1, 2])
diff --git a/python/ray/rllib/policy_gradient/agent.py b/python/ray/rllib/policy_gradient/agent.py
index ef1499c0b..85de0d06f 100644
--- a/python/ray/rllib/policy_gradient/agent.py
+++ b/python/ray/rllib/policy_gradient/agent.py
@@ -11,7 +11,7 @@ from tensorflow.python import debug as tf_debug
 import ray
 
 from ray.rllib.parallel import LocalSyncParallelOptimizer
-from ray.rllib.policy_gradient.distributions import Categorical, DiagGaussian
+from ray.rllib.models import ModelCatalog
 from ray.rllib.policy_gradient.env import BatchedEnv
 from ray.rllib.policy_gradient.loss import ProximalPolicyLoss
 from ray.rllib.policy_gradient.filter import MeanStdFilter
@@ -33,8 +33,8 @@ class Agent(object):
     network weights. When run as a remote agent, only this graph is used.
     """
 
-    def __init__(self, name, batchsize, preprocessor, config, logdir,
-                 is_remote):
+    def __init__(
+            self, name, batchsize, preprocessor, config, logdir, is_remote):
         if is_remote:
             os.environ["CUDA_VISIBLE_DEVICES"] = ""
             devices = ["/cpu:0"]
@@ -54,37 +54,30 @@ class Agent(object):
         self.sess = tf.Session(config=config_proto)
         if config["use_tf_debugger"] and not is_remote:
             self.sess = tf_debug.LocalCLIDebugWrapperSession(self.sess)
-            self.sess.add_tensor_filter("has_inf_or_nan",
-                                        tf_debug.has_inf_or_nan)
+            self.sess.add_tensor_filter(
+                "has_inf_or_nan", tf_debug.has_inf_or_nan)
 
         # Defines the training inputs.
-        self.kl_coeff = tf.placeholder(name="newkl", shape=(),
-                                       dtype=tf.float32)
-        self.observations = tf.placeholder(tf.float32,
-                                           shape=(None,) + preprocessor.shape)
+        self.kl_coeff = tf.placeholder(
+            name="newkl", shape=(), dtype=tf.float32)
+        self.observations = tf.placeholder(
+            tf.float32, shape=(None,) + preprocessor.shape)
         self.advantages = tf.placeholder(tf.float32, shape=(None,))
 
         action_space = self.env.action_space
         if isinstance(action_space, gym.spaces.Box):
-            # The first half of the dimensions are the means, the second half
-            # are the standard deviations.
-            self.action_dim = action_space.shape[0]
-            self.action_shape = (self.action_dim,)
-            self.logit_dim = 2 * self.action_dim
-            self.actions = tf.placeholder(tf.float32,
-                                          shape=(None, self.action_dim))
-            self.distribution_class = DiagGaussian
+            self.actions = tf.placeholder(
+                tf.float32, shape=(None, action_space.shape[0]))
         elif isinstance(action_space, gym.spaces.Discrete):
-            self.action_dim = action_space.n
-            self.action_shape = ()
-            self.logit_dim = self.action_dim
             self.actions = tf.placeholder(tf.int64, shape=(None,))
-            self.distribution_class = Categorical
         else:
-            raise NotImplemented("action space" + str(type(action_space)) +
-                                 "currently not supported")
-        self.prev_logits = tf.placeholder(tf.float32,
-                                          shape=(None, self.logit_dim))
+            raise NotImplemented(
+                "action space" + str(type(action_space)) +
+                "currently not supported")
+        self.distribution_class, self.logit_dim = ModelCatalog.get_action_dist(
+            action_space)
+        self.prev_logits = tf.placeholder(
+            tf.float32, shape=(None, self.logit_dim))
 
         assert config["sgd_batchsize"] % len(devices) == 0, \
             "Batch size must be evenly divisible by devices"
@@ -99,7 +92,8 @@ class Agent(object):
             return ProximalPolicyLoss(
                 self.env.observation_space, self.env.action_space,
                 obs, advs, acts, plog, self.logit_dim,
-                self.kl_coeff, self.distribution_class, self.config, self.sess)
+                self.kl_coeff, self.distribution_class, self.config,
+                self.sess)
 
         self.par_opt = LocalSyncParallelOptimizer(
             tf.train.AdamOptimizer(self.config["sgd_stepsize"]),
@@ -118,14 +112,13 @@ class Agent(object):
             self.mean_kl = tf.reduce_mean(
                 tf.stack(values=[policy.mean_kl for policy in policies]), 0)
             self.mean_entropy = tf.reduce_mean(
-                tf.stack(values=[policy.mean_entropy for policy in policies]),
-                0)
+                tf.stack(
+                    values=[policy.mean_entropy for policy in policies]), 0)
 
         # References to the model weights
         self.common_policy = self.par_opt.get_common_loss()
         self.variables = ray.experimental.TensorFlowVariables(
-            self.common_policy.loss,
-            self.sess)
+            self.common_policy.loss, self.sess)
         self.observation_filter = MeanStdFilter(preprocessor.shape, clip=None)
         self.reward_filter = MeanStdFilter((), clip=5.0)
         self.sess.run(tf.global_variables_initializer())
@@ -139,8 +132,8 @@ class Agent(object):
              trajectories["logprobs"]],
             full_trace=full_trace)
 
-    def run_sgd_minibatch(self, batch_index, kl_coeff, full_trace,
-                          file_writer):
+    def run_sgd_minibatch(
+            self, batch_index, kl_coeff, full_trace, file_writer):
         return self.par_opt.optimize(
             self.sess,
             batch_index,
diff --git a/python/ray/rllib/policy_gradient/env.py b/python/ray/rllib/policy_gradient/env.py
index 74795b8f4..7dcaf2f9b 100644
--- a/python/ray/rllib/policy_gradient/env.py
+++ b/python/ray/rllib/policy_gradient/env.py
@@ -55,8 +55,7 @@ class BatchedEnv(object):
                 observations.append(np.zeros(self.shape))
                 rewards.append(0.0)
                 continue
-            observation, reward, done, info = self.envs[i].step(
-                action if len(action) > 1 else action[0])
+            observation, reward, done, info = self.envs[i].step(action)
             if render:
                 self.envs[0].render()
             observations.append(self.preprocessor(observation))
diff --git a/python/ray/rllib/policy_gradient/loss.py b/python/ray/rllib/policy_gradient/loss.py
index 211128727..ef40f577a 100644
--- a/python/ray/rllib/policy_gradient/loss.py
+++ b/python/ray/rllib/policy_gradient/loss.py
@@ -4,8 +4,8 @@ from __future__ import print_function
 
 import gym.spaces
 import tensorflow as tf
-from ray.rllib.policy_gradient.models.visionnet import vision_net
-from ray.rllib.policy_gradient.models.fcnet import fc_net
+
+from ray.rllib.models import ModelCatalog
 
 
 class ProximalPolicyLoss(object):
@@ -21,11 +21,8 @@ class ProximalPolicyLoss(object):
         # Saved so that we can compute actions given different observations
         self.observations = observations
 
-        if len(observation_space.shape) > 1:
-            self.curr_logits = vision_net(observations, num_classes=logit_dim)
-        else:
-            assert len(observation_space.shape) == 1
-            self.curr_logits = fc_net(observations, num_classes=logit_dim)
+        self.curr_logits = ModelCatalog.get_model(
+            observations, logit_dim).outputs
         self.curr_dist = distribution_class(self.curr_logits)
         self.sampler = self.curr_dist.sample()
 
diff --git a/python/ray/rllib/policy_gradient/models/__init__.py b/python/ray/rllib/policy_gradient/models/__init__.py
deleted file mode 100644
index e69de29bb..000000000
diff --git a/python/ray/rllib/policy_gradient/models/fcnet.py b/python/ray/rllib/policy_gradient/models/fcnet.py
deleted file mode 100644
index 057b2004d..000000000
--- a/python/ray/rllib/policy_gradient/models/fcnet.py
+++ /dev/null
@@ -1,38 +0,0 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
-import tensorflow as tf
-import tensorflow.contrib.slim as slim
-
-import numpy as np
-
-
-def normc_initializer(std=1.0):
-    def _initializer(shape, dtype=None, partition_info=None):
-        out = np.random.randn(*shape).astype(np.float32)
-        out *= std / np.sqrt(np.square(out).sum(axis=0, keepdims=True))
-        return tf.constant(out)
-    return _initializer
-
-
-def fc_net(inputs, num_classes=10, logstd=False):
-    with tf.name_scope("fc_net"):
-        fc1 = slim.fully_connected(inputs, 128,
-                                   weights_initializer=normc_initializer(1.0),
-                                   scope="fc1")
-        fc2 = slim.fully_connected(fc1, 128,
-                                   weights_initializer=normc_initializer(1.0),
-                                   scope="fc2")
-        fc3 = slim.fully_connected(fc2, 128,
-                                   weights_initializer=normc_initializer(1.0),
-                                   scope="fc3")
-        fc4 = slim.fully_connected(fc3, num_classes,
-                                   weights_initializer=normc_initializer(0.01),
-                                   activation_fn=None, scope="fc4")
-        if logstd:
-            logstd = tf.get_variable(name="logstd", shape=[num_classes],
-                                     initializer=tf.zeros_initializer)
-            return tf.concat(1, [fc4, logstd])
-        else:
-            return fc4
diff --git a/python/ray/rllib/policy_gradient/models/visionnet.py b/python/ray/rllib/policy_gradient/models/visionnet.py
deleted file mode 100644
index 2b03b2ff7..000000000
--- a/python/ray/rllib/policy_gradient/models/visionnet.py
+++ /dev/null
@@ -1,16 +0,0 @@
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
-import tensorflow as tf
-import tensorflow.contrib.slim as slim
-
-
-def vision_net(inputs, num_classes=10):
-    with tf.name_scope("vision_net"):
-        conv1 = slim.conv2d(inputs, 16, [8, 8], 4, scope="conv1")
-        conv2 = slim.conv2d(conv1, 32, [4, 4], 2, scope="conv2")
-        fc1 = slim.conv2d(conv2, 512, [10, 10], padding="VALID", scope="fc1")
-        fc2 = slim.conv2d(fc1, num_classes, [1, 1], activation_fn=None,
-                          normalizer_fn=None, scope="fc2")
-        return tf.squeeze(fc2, [1, 2])
diff --git a/python/ray/rllib/policy_gradient/policy_gradient.py b/python/ray/rllib/policy_gradient/policy_gradient.py
index 760ca5320..df2e2b0ee 100644
--- a/python/ray/rllib/policy_gradient/policy_gradient.py
+++ b/python/ray/rllib/policy_gradient/policy_gradient.py
@@ -48,8 +48,7 @@ class PolicyGradient(Algorithm):
 
         Algorithm.__init__(self, env_name, config, upload_dir=upload_dir)
 
-        # TODO(ekl): The preprocessor should be associated with the env
-        # elsewhere.
+        # TODO(ekl): preprocessor should be associated with the env elsewhere
         if self.env_name == "Pong-v0":
             preprocessor = AtariPixelPreprocessor()
         elif self.env_name == "Pong-ram-v3":
@@ -58,6 +57,8 @@ class PolicyGradient(Algorithm):
             preprocessor = NoPreprocessor()
         elif self.env_name == "Walker2d-v1":
             preprocessor = NoPreprocessor()
+        elif self.env_name == "Humanoid-v1":
+            preprocessor = NoPreprocessor()
         else:
             preprocessor = AtariPixelPreprocessor()
 
@@ -93,8 +94,8 @@ class PolicyGradient(Algorithm):
             if config["model_checkpoint_file"]:
                 checkpoint_path = saver.save(
                     model.sess,
-                    os.path.join(self.logdir,
-                                 config["model_checkpoint_file"] % j))
+                    os.path.join(
+                        self.logdir, config["model_checkpoint_file"] % j))
                 print("Checkpoint saved in file: %s" % checkpoint_path)
         checkpointing_end = time.time()
         weights = ray.put(model.get_weights())
@@ -135,8 +136,8 @@ class PolicyGradient(Algorithm):
         for i in range(config["num_sgd_iter"]):
             sgd_start = time.time()
             batch_index = 0
-            num_batches = (int(tuples_per_device) //
-                           int(model.per_device_batch_size))
+            num_batches = (
+                int(tuples_per_device) // int(model.per_device_batch_size))
             loss, kl, entropy = [], [], []
             permutation = np.random.permutation(num_batches)
             while batch_index < num_batches:
@@ -155,8 +156,8 @@ class PolicyGradient(Algorithm):
             kl = np.mean(kl)
             entropy = np.mean(entropy)
             sgd_end = time.time()
-            print("{:>15}{:15.5e}{:15.5e}{:15.5e}".format(i, loss, kl,
-                                                          entropy))
+            print(
+                "{:>15}{:15.5e}{:15.5e}{:15.5e}".format(i, loss, kl, entropy))
 
             values = []
             if i == config["num_sgd_iter"] - 1:
diff --git a/python/ray/rllib/policy_gradient/test/test.py b/python/ray/rllib/policy_gradient/test/test.py
index 325ee437f..a9ff78d4e 100644
--- a/python/ray/rllib/policy_gradient/test/test.py
+++ b/python/ray/rllib/policy_gradient/test/test.py
@@ -7,11 +7,12 @@ import numpy as np
 import tensorflow as tf
 from numpy.testing import assert_allclose
 
-from ray.rllib.policy_gradient.distributions import Categorical
+from ray.rllib.models.action_dist import Categorical
 from ray.rllib.policy_gradient.utils import flatten, concatenate
 
 
-class DistibutionsTest(unittest.TestCase):
+# TODO(ekl): move to rllib/models dir
+class DistributionsTest(unittest.TestCase):
 
     def testCategorical(self):
         num_samples = 100000