Practical Object Oriented Design in Ruby: An Agile Primer (Addison-Wesley)
Friday, 25 January 2013

The Web is awash in Ruby code that is now virtually impossible to change or extend. This guide to writing more maintainable and manageable Ruby helps you solve that problem by using powerful real-world object-oriented design techniques, which it thoroughly explains using simple and practical Ruby examples.
<ASIN:0321721330>