I am currently reading a new testing book, How to Break Software: A practical guide to testing, by James Whittaker, ISBN:0-201-79619-8, Addison-Wesley, 2003. This is the book I mentioned in the CS540 lecture class. It approaches testing as a series of attacks, similar in approach to how secure systems are challenged. It is a good addition to any testing program. He stresses ingenuity and flexibility in testing. Recommended!