Gray Hat Hacking

A fantastic book for anyone looking to learn the tools and techniques needed to break in and stay in. Very highly recommended whether you are a seasoned professional or just starting out in the security business. Basically divided into five parts :-
Part I: Introduction to Ethical Disclosure,
Part II: Penetration Testing and Tools ,
Part III: Exploits 101,
Part IV: Vulnerability Analysis,
Part V: Malware Analysis