diff --git a/gapi.auth2/gapi.auth2.d.ts b/gapi.auth2/gapi.auth2.d.ts
index 7da32c9a1..c5375f9fe 100644
--- a/gapi.auth2/gapi.auth2.d.ts
+++ b/gapi.auth2/gapi.auth2.d.ts
@@ -7,16 +7,190 @@
 
 declare module gapi.auth2 {
 
-  // TODO
+  /**
+   * GoogleAuth is a singleton class that provides methods to allow the user to sign in with a Google account,
+   * get the user's current sign-in status, get specific data from the user's Google profile,
+   * request additional scopes, and sign out from the current account.
+   */
   export class GoogleAuth {
+    /**
+     * Calls the onInit function when the GoogleAuth object is fully initialized, or calls the onFailure function if
+     * initialization fails.
+     */
+    then(onInit: () => any, onFailure: (reason: string) => any);
 
+    /**
+     * Signs in the user with the options specified to gapi.auth2.init().
+     */
+    signIn(): any;
+
+    /**
+     * Signs in the user using the specified options.
+     */
+    signIn(options?: {
+      app_package_name?: string;
+      fetch_basic_profile?: boolean;
+      prompt?: boolean;
+      scope?: string;
+    }, optionBuilder?: SigninOptionsBuilder): any;
+
+    /**
+     * Signs out all accounts from the application.
+     */
+    signOut(): any;
+
+    /**
+     * Revokes all of the scopes that the user granted.
+     */
+    disconnect(): any;
+
+    /**
+     * Get permission from the user to access the specified scopes offline.
+     */
+    grantOfflineAccess(options: {
+      scope?: string;
+      redirect_uri?: string;
+    }): any;
+
+    /**
+     * Attaches the sign-in flow to the specified container's click handler.
+     */
+    attachClickHandler(container: any, options: {
+      app_package_name?: string;
+      fetch_basic_profile?: boolean;
+      prompt?: boolean;
+      scope?: string;
+    }, onsuccess: () => any, onfailure: (reason: string) => any): any;
   }
 
-  // TODO
-  export class GoogleUser {
+  export module GoogleAuth {
+    export interface isSignedIn{
+      /**
+       * Returns whether the current user is currently signed in.
+       */
+      get(): boolean;
 
+      /**
+       * Listen for changes in the current user's sign-in state.
+       */
+      listen(listener: (signedIn: boolean) => any): void;
+    }
+
+    export interface currentUser {
+      /**
+       * Returns a GoogleUser object that represents the current user. Note that in a newly-initialized
+       * GoogleAuth instance, the current user has not been set. Use the currentUser.listen() method or the
+       * GoogleAuth.then() to get an initialized GoogleAuth instance.
+       */
+      get(): GoogleUser;
+
+      /**
+       * Listen for changes in currentUser.
+       */
+      listen(listener: (user: GoogleUser) => any): void;
+    }
   }
 
+  export class SigninOptionsBuilder {
+    setAppPackageName(name: string): any;
+    setFetchBasicProfile(fetch: boolean): any;
+    setPrompt(prompt: string): any;
+    setScope(scope: string): any;
+  }
+
+  export interface BasicProfile {
+    getId(): string;
+    getName(): string;
+    getImageUrl(): string;
+    getEmail(): string;
+  }
+
+  export interface AuthResponse {
+    access_token: string;
+    id_token: string;
+    login_hint: string;
+    scope: string;
+    expires_in: string;
+    first_issued_at: string;
+    expires_at: string;
+  }
+
+  /**
+   * A GoogleUser object represents one user account.
+   */
+  export interface GoogleUser {
+    /**
+     * Get the user's unique ID string.
+     */
+    getId(): string;
+
+    /**
+     * Returns true if the user is signed in.
+     */
+    isSignedIn(): boolean;
+
+    /**
+     * Get the user's Google Apps domain if the user signed in with a Google Apps account.
+     */
+    getHostedDomain(): string;
+
+    /**
+     * Get the scopes that the user granted as a space-delimited string.
+     */
+    getGrantedScopes(): string;
+
+    /**
+     * Get the user's basic profile information.
+     */
+    getBasicProfile(): BasicProfile;
+
+    /**
+     * Get the response object from the user's auth session.
+     */
+    getAuthResponse(): AuthResponse;
+
+    /**
+     * Returns true if the user granted the specified scopes.
+     */
+    hasGrantedScopes(scopes: string): boolean;
+
+    /**
+     * Signs in the user. Use this method to request additional scopes for incremental
+     * authorization or to sign in a user after the user has signed out.
+     * When you use GoogleUser.signIn(), the sign-in flow skips the account chooser step.
+     * See GoogleAuth.signIn().
+     */
+    signIn(options?: {
+      app_package_name?: string;
+      fetch_basic_profile?: boolean;
+      prompt?: boolean;
+      scope?: string;
+    }, optionBuilder?: SigninOptionsBuilder): any;
+
+    /**
+     *
+     */
+    grant(options?: {
+      app_package_name?: string;
+      fetch_basic_profile?: boolean;
+      prompt?: boolean;
+      scope?: string;
+    }, optionBuilder?: SigninOptionsBuilder): any;
+
+    /**
+     * Get permission from the user to access the specified scopes offline.
+     * When you use GoogleUser.grantOfflineAccess(), the sign-in flow skips the account chooser step.
+     * See GoogleUser.grantOfflineAccess().
+     */
+    grantOfflineAccess(scopes: string): void;
+
+    /**
+     * Revokes all of the scopes that the user granted.
+     */
+    disconnect(): void;
+  }
+
+
   export function init(params: {
       /**
        * The app's client ID, found and created in the Google Developers Console.
@@ -48,28 +222,61 @@ declare module gapi.auth2 {
 
       /**
        * Used only for OpenID 2.0 client migration. Set to the value of the realm that you are currently using for OpenID 2.0,
-       * as described in OpenID 2.0 (Migration) https://developers.google.com/accounts/docs/OpenID#openid-connect.
+       * as described in <a href="https://developers.google.com/accounts/docs/OpenID#openid-connect">OpenID 2.0 (Migration)</a>.
        */
       openid_realm?: string;
   }): GoogleAuth;
 
-  // TODO
-  export function getAuthInstance();
+  /**
+   * Returns the GoogleAuth object. You must initialize the GoogleAuth object with gapi.auth2.init() before calling this method.
+   */
+  export function getAuthInstance(): GoogleAuth;
 }
 
-declare module gapi.signin {
-  // TODO
+declare module gapi.signin2 {
+
   export function render(id: any, options: {
     /**
      * The auth scope or scopes to authorize. Auth scopes for individual APIs can be found in their documentation.
      */
     scope?: string;
+
+    /**
+     * The width of the button in pixels (default: 120).
+     */
     width?: number;
+
+    /**
+     * The height of the button in pixels (default: 36).
+     */
     height?: number;
+
+    /**
+     * Display long labels such as "Sign in with Google" rather than "Sign in" (default: false).
+     */
     longtitle?: boolean;
+
+    /**
+     * The color theme of the button: either light or dark (default: light).
+     */
     theme?: string;
+
+    /**
+     * The callback function to call when a user successfully signs in.
+     * This function must take one argument: an instance of gapi.auth2.GoogleUser (default: none).
+     */
     onsuccess?: any;
+
+    /**
+     * The callback function to call when sign-in fails. This function takes no arguments (default: none).
+     */
     onfailure?: any;
+
+    /**
+     * The package name of the Android app to install over the air. See
+     * <a href="https://developers.google.com/identity/sign-in/web/android-app-installs">Android app installs from your web site</a>.
+     * Optional. (default: none)
+     */
     app_package_name?: string;
   });
 }