Hunt, Andrew and Thomas, David. The Pragmatic Progammer. Reading, MA, USA: Addison Wesley Longman Inc., October 1999. ISBN: 020161622X
This classic software engineering book covers best practices for being more productive. Anyone who is serious about developing high quality software must read this book. This is the second time I've read it and I found that I still enjoyed it and was reminded of things that I had forgotten. Some parts of it are starting to become out of date, but that doesn't prevent it from being excellent. However, it will definitely be due for a second edition in a few more years.