<font size="2" face="Verdana, Arial, Helvetica">If you do decide to make purchase one of these books, please consider linking to Amazon.com via a link on the QAlinks Web page - Amazon will then credit QAForums for the referral and you will (at no additional cost to yourself) help meet the costs of funding this community Web site.
I have found "The Web Testing Handbook" book to be the most helpful of all. It's written by Steven Splaine and Stefan Jaskiel. Definitely an excellent source of reference for all testers. i use it all the time.