Refactoring: Improving the Design of Existing Code (Addison-Wesley Signature Series (Fowler))

Martin Fowler’s guide to reworking bad code into well-structured code
Refactoring improves the design of existing code and enhances software maintainability, as well as making existing code easier to understand. Original Agile Manifesto signer and software development thought leader, Martin Fowler, provides a catalog of refactorings that explains why you should refactor; how to recognize code that needs refactoring; and how to actually do it successfully, no matter what language you use.
Refactoring principles: understand the process and general principles of refactoring
Code smells: recognize “bad smells” in code that signal opportunities to refactor
Application improvement: quickly apply useful refactorings to make a program easier to comprehend and change
Building tests: writing good tests increases a programmer’s effectiveness
Moving features: an important part of refactoring is moving elements between contexts
Data structures: a collection of refactorings to organize data, an important role in programs
Conditional Logic: use refactorings to make conditional sections easier to understand