Appendix B. Ruby Reference
This appendix provides several reference sections that you'll find useful from time to time while developing applications with Ruby. More specifically, what's in this appendix is limited to direct reference information that you might find useful while otherwise using this book. For a list of external resources, such as web sites and mailing lists you can query for more detailed or up-to-date information, refer to Appendix C. Over time, it's essential you learn to use Ruby's online references, as they'll be updated in line with how the Ruby language develops. They'll also open your mind to new possibilities and advanced techniques not covered in this book.
Useful Classes and Methods
The following subsections highlight several ...