Kevin L. Polk, PhD, is a clinical psychologist who has been a practicing for twenty-three years, primarily helping veterans and others with troubling trauma memories. For the past eight years, he has dedicated himself to the study of acceptance and commitment therapy (ACT), spending close to 20,000 hours studying the philosophy and theory behind ACT, and learning and designing ACT interventions. He is a peer-reviewed ACT trainer who is passionate about teaching others how to use the matrix to increase psychological flexibility and valued living. Find out more at www.drkevinpolk.com.