Here is a list of the books mentioned in my talk on Large Scale Refactoring.
Refactoring: Improving the Design of Existing Code is the original book written by Martin Fowler. It is a must have to anyone doing object-oriented programming.
Refactoring to Patterns is a very good book written by Joshua Kerievsky. This book is one of the best books I have read on patterns. It shows how some smells in code can be removed by refactoring them into design patterns.
Refactoring Databases: Evolutionary Database Design is a superb book that deals with refactoring databases. If you do any work with databases, you have to read this book.
Refactoring in Large Software Projects is a book about how to refactor large software systems. It is an OK book, but very far from the other refactoring books mentioned above.
The Mythical Man-Month by Fred Brooks is the classic, more than 30 years old, dealing with problems in software development. It is well worth reading. You can also listen to his talk at OOPSLA 2007, which is very, very good.