I've only read chapter seven of Williams' "Buddhist Thought," which was actually written by Anthony Tribe. However, on the strength of this one chapter alone, I feel moved to recommend this book. Put simply, chapter seven is the single best brief introductory overview of tantric Buddhism that I have ever encountered. I was stunned by the amount of useful, intelligent, accurate information that was provided in such a short space, especially since this is one of the most misunderstood topics in all of Buddhist Studies. Bravo to Tribe; this chapter alone is probably worth the price of the book, and if the rest of the book is up to this standard, this is a volume of rare excellence indeed.
Williams trumps his masterful classic "Mahayana Buddhism" with an even better book. This is vastly superior to any previous effort (David Kalupahana, eat your heart out!). Williams has a superb talent for explicating difficulty ideas with clarity and simplicity, and his prose has a pleasant and inviting tone. He is also completely up to date on the state of current specialized scholarship, so even those readers already endowed with a good grasp of the development of Buddhist philosophy will find an abundance of interesting material here. This book is destined to be a classic.