Amazon.com just posted my five star review of Mike Schiffman's Building Open Source Network Security Tools. From the review:
"Books on hacking, cracking, exploiting, and breaking software seem to get all of the attention in the security world. However, we need more works like Mike Schiffman's 'Building Open Source Network Security Tools' (BOSNST). I regret having waited so long to read BOSNST, but I'm glad I did. Schiffman's book is for people who want to build, not break, software, and the way he describes how to create tools is enlightening.
The major theme I captured from BOSNST was the importance of creating useful code libraries. Six of the book's 12 chapters focus on libraries which provide functions for application programmers. While not all have gained the same amount of fame or use, the author's approach remains sound. Libraries are the building blocks around which numerous tools can and should be built."
Mike is a researcher at Cisco's Critical Infrastructure Assurance Group. He appears to be working on a new book called Modern Network Infrastructure Security, Volume I: The Protocols with Jeremy Rauch. I believe the new book will be great.