A must read for anyone interested in web application security.

Probably the best book on SQL Injection out there.

The defiintive guide to NMAP, written by it's creator.

Brilliant book: Interesting material, well-documented, includes a lot of neat tricks. Kept me sleepless for a week; the first 4 nights I was busy reading it, and the last 3 I was coding like mad :-)

A great book that is both novel and informative. An added bonus is that the sales support Johnny Long and Hackers For Charity.