diff --git a/doc/Makefile b/doc/Makefile
index befa2087..093f65ea 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -4,7 +4,7 @@
 # You can set these variables from the command line.
 PYTHON        ?= python
 SPHINXOPTS    ?=
-SPHINXBUILD   ?= sphinx-build
+SPHINXBUILD   ?= python $(shell which sphinx-build)
 PAPER         ?=
 
 # Internal variables.
diff --git a/doc/README.md b/doc/README.md
new file mode 100644
index 00000000..48e26788
--- /dev/null
+++ b/doc/README.md
@@ -0,0 +1,5 @@
+# Building docs #
+To build docs, run `make` in this directory. `make help` lists all targets.
+
+## Requirements ##
+Sphinx is needed to build doc. Install with `pip install sphinx`.