Get Out of Your Mind and Into Your Life is the first self-help book on ACT written by Steven Hayes, the primary originator of the ACT approach. This book is a great introduction to ACT for both professionals and non professionals. It has a lot of exercises and worksheets that allows you to work through the ACT process experientially on your own.

A Practical Guide to Acceptance and Commitment Therapy is the first edited book devoted to ACT. Chapters focus on theory, core competencies, case formulation, affective disorders, anxiety disorders, PTSD, substance abuse, psychosis, multi-problem patients, children and families, stress/workplace, medical settings, chronic pain, and groups.

Acceptance and Mindfulness at Work is the most comprehensive book on applying ACT principles to work settings. Sure to be an important book for those interested in applying the ACT model outside of the therapy realm. Sometimes ACT has been retermed Acceptance and Commitment Training for use in its non-clinical applications. ACT has been applied to work settings in a few clinical trials now and has done well compared to accepted, evidence-based approaches.

Acceptance & Commitment Therapy for the Treatment of Post-Traumatic Stress Disorder is the first ACT text for PTSD. I haven't read it myself yet, but you can check out the review on Amazon.com by clicking on the image to the left.