For 14 years, Jeff Rubin's Handbook has been one of the most useful resources for anyone interested in doing usability testing.
Now Dana Chisnell has done an outstanding job of bringing it up to date--and much more. From cover to cover, it's full of useful insights about every aspect of testing, based on the cumulative experience of two seasoned---and very smart--practitioners. And it's a pleasure to read.
If you do usability testing, or you're interested in learning how it's done, this book is a must-read.