Russell Harris Russell Harris, M.D., is a medical professional, psychotherapist, and best-selling author of The Happiness Trap. As an international expert on Acceptance and Commitment Therapy, Russ is renowned for his ability to make complex subject matter simple and easy-to-understand. He also regularly presents ACT workshops at both national and international conferences. His book The Happiness Trap is now widely used not just as a self-help book for clients, but as a self-teaching aid for therapists who wish to learn ACT quickly and easily without getting bogged down in technical jargon.