Refactoring is about improving the design of existing code. It is the process of changing a software system in such a way that it does not alter the external behavior of the code, yet improves its internal structure. With refactoring you can even take a bad design and rework it into a good one. This book offers a thorough discussion of the principles of refactoring, including where to spot opportunities for refactoring, and how to set up the required tests. There is also a catalog of more than 40 proven refactorings with details as to when and why to use the refactoring, step by step instructions for implementing it, and an example illustrating how it works The book is written using Java as its principle language, but the ideas are applicable to any OO language.About the AuthorMartin Fowler is the Chief Scientist of ThoughtWorks, an enterprise-application development and delivery company. He's been applying object-oriented techniques to enterprise software development for over a decade. He is notorious for his work on patterns, the UML, refactoring, and agile methods. Martin lives in Melrose, Massachusetts, with his wife, Cindy, and a very strange cat. His homepage is http://martinfowler.com.Kent Beck consistently challenges software engineering dogma, promoting ideas like patterns, test-driven development, and Extreme Programming. Currently affiliated with Three Rivers Institute and Agitar Software, he is the author of many Addison-Wesley titles.John Brant and Don Roberts are the authors of the Refactoring Browser for Smalltalk, which is found at http://st-www.cs.uiuc.edu/~brant/RefactoringBrowser/. They are also consultants who have studied both the practical and theoretical aspects of refactoring for six years.William Opdyke's doctoral research on refactoring object-oriented frameworks at the University of Illinois led to the first major publication on this topic. He is currently a Distinguished Member of Technical Staff at Lucent Technologies/Bell Laboratories.John Brant and Don Roberts are the authors of the Refactoring Browser for Smalltalk, which is found at http://st-www.cs.uiuc.edu/~brant/RefactoringBrowser/. They are also consultants who have studied both the practical and theoretical aspects of refactoring for six years.