Book title - Web Hacking Attacks and Defense
Publisher - Addison-Wesley
ISBN - 0-201-76176-9
Authors - McClure/Shah/Shah

This book should be in every webmaster and web developers library.

The authors present in a very understandable way the vulnerabilies and fixes for many different web exploits.

A basic summary of covered topics:

Web Languages
Web Data base server
Shopping carts
Protocols
Detailed description of URL's and URL encoding and abusing
Java
Buffer Overflows
( The list is much larger )

They also provide several case studies so you can see how it is done in the real world

There is an incredible amount of information in this book

Enjoy