This paper introduces Acceptance and commitment Therapy (ACT) as one of the newer contextualist behaviour therapies. A brief history of the development of ACT is outlined. The concepts of equivalence and laterality and the important relationship between Relational Frame Theory and ACT are then described. The “hexagram” summary of the six core linked processes in ACT is presented and, finally, the research evidence to support the effectiveness of ACT applied to a range of clinical conditions and client groups is summarized.
