Practical Object-Oriented Design, An Agile Primer Using Ruby (POODR) is a programmers tale about how to write object-oriented code.

Written by Sandi Metz, it explains object-oriented design (OOD) using realistic, understandable examples.   POODR* is a practical, readable introduction to how OOD can lower your costs and improve your applications.

POODR will help you:

• Decide what belongs in a single class

• Avoid entangling objects that should be kept separate

• Define flexible interfaces among objects

• Reduce programming overhead costs with duck typing

• Successfully apply inheritance

• Build objects via composition

• Design cost-effective tests

• Craft simple, straightforward, understandable code