Acceptance and Commitment Therapy (ACT) is a rarity in that it may be more easily understood via a workbook than by its more wordy, academese-heavy basic texts. Get Out of Your Mind and Into Your Life, by Steven Hayes is a nice intertwining of text and exercises, a solid example of the emerging "third wave" cognitive behavioral tradition.
For those who want to dig deeper into ACT (and its foundation, Relational Frame Theory), try joining the ACT Yahoo Group. Also, ACT workshops, I'm told, are among the most wrenching/satisfying out there. Enjoy.