You can create your own local version of the consolidated Rails API documentation.
Just type the following commands at a command prompt:
<code>$ rails new dummy_app
$ cd dummy_app
$ dummy_app> rake doc:rails
The last step takes a while. When it finishes, you’ll have the Rails API documentation in a directory tree starting at doc/api. We suggest moving this folder to your desktop and then deleting the dummy_app tree. To view the Rails API documentation, open the location doc/api/index.html with your browser.