Writing a book on Java design patterns has been a fascinating challenge. Design patterns are intellectually recursive; that is, every time that you think that you've wrapped up a good explanation of one, another turn of the crank occurs to you or is suggested by someone else. So, while writing is essentially a solitary task, I had a lot of help and support.

Foremost, I thank Roy Byrd and Alan Marwick of IBM Research for encouraging me to tackle this book and providing lots of support during the manuscript's genesis and revision. I also especially thank Nicole Cooper for editing my first draft; she definitely improved its clarity and accuracy.

The design pattern community (informally called the "Pattern-nostra") were also a great help. In particular, I thank both John Vlissides and Ken Arnold for their careful and thoughtful reading of the manuscript. Among the many others, I thank Ralph Johnson, Sherman Alpert, Zunaid Kazi, Colin Harrison, and Hank Stuck. I'm also grateful to John Dorsey and Tyler Sperry at JavaPro magazine for their encouragement and editorial suggestions on some of the columns that I wrote that later became parts of this book. Thanks also to Herb Chong and Mary Neff for lending their names and part of their project descriptions to the case studies chapter. Finally, thanks to my wife Vicki, who provided endless support during the ups and downs of endless writing and seemingly endless revision.