In this issue of Psychiatric Clinics, guest editors Drs. Michael Levin and Sam Spencer bring their considerable expertise to the topic of Acceptance and Commitment Therapy. Over the last 25 years, acceptance and commitment therapy (ACT), an action-oriented approach to psychotherapy, has become widely used and is accepted as an effective technique for treating a variety of physical and mental conditions. In this issue, top experts discuss ACT for anxiety disorders, psychosis, substance use disorders, PTSD, hoarding disorder, psychiatric conditions in youth, and more.