- Alistair Cockburn. Agile Software Development: The Cooperative Game. Second edition. (Addison-Wesley, 2006).
- Allen Holub. Holub on Patterns: Learning Design Patterns by Looking at Code. (APress, 2004).
- Andrew Hunt. Pragmatic Thinking and Learning: Refactor your Wetware. (Pragmatic Bookshelf, 2008).
- Andrew Hunt and David Thomas. The Pragmatic Programmer: From Journeyman to Master. (Addison-Wesley, 1999).
- Robert C. Martin. Clean Code: A Handbook of Agile Software Craftsmanship. (Prentice Hall, 2008).
All of these books are worth reading, but where you start depends on your interests. If you are interested specifically in object-oriented design, definitely start with Holub on Patterns. Clean Code and The Pragmatic Programmer are replete with bite-size tips that can immediately make you a better professional. Pragmatic Thinking and Learning is not about technology per se, but rather it is about how to be a more effective learner. Finally, Cockburn's book is the largest and most academic on the list, but it provides tremendous insight into how one can approach software development methodologies from a perspective that is both humanistic and scientific.