When cognitive behavior therapy emerged in 1950s, driven by the work of Albert Ellis and Aaron Beck, basic behavior principles were largely sidelined in clinical psychology curricula. Issues in cognition became the focus of case conceptualization and intervention planning for most therapists. But as the new third-wave behavior therapies begin to address weaknesses in the traditional cognitive behavioral models-principally the modest effectiveness of thought stopping and cognitive restructuring techniques-basic behavior principles are once again attracting the interest of front-line clinicians. Many of today’s clinicians, though, received their training during the years in which classical behaviorism was not a major part of clinical education. In order to make the best use of the new contextual behaviorism, they need to revisit basic behavioral principles from a practical angle. This book addresses this need.