Kirk D. Strosahl, PhD, is cofounder of acceptance and commitment therapy (ACT), a cognitive behavioral approach that has gained widespread adoption in the mental health and substance-abuse communities. He is coauthor of Brief Interventions for Radical Change and other core ACT books. Strosahl works as a practicing psychologist at Central Washington Family Medicine, a community health center providing health care to medically underserved patients. He also teaches family medicine physicians how to use the principles of mindfulness and acceptance in general practice. Strosahl lives in Zillah, WA.