The Book of Ruby covers many of the classes and methods in the standard Ruby library—but by no means all of them! At some stage, therefore, you will need to refer to documentation on the full range of classes used by Ruby. Fortunately, the Ruby class library contains embedded documentation that has been extracted and compiled into an easily browsable reference, which is available in several formats. For example, you can find the online documentation for Ruby 1.9 at http://www.ruby-doc.org/ruby-1.9/index.html. For Ruby 1.8, go to http://www.ruby-doc.org/ruby-1.8/index.html.

Okay, that’s enough of the preamble—let’s get down to work.