Matthew McKay, PhD, is a professor at the Wright Institute in Berkeley, CA. He has authored and coauthored numerous books, including The Dialectical Behavior Therapy Skills Workbook, Self-Esteem, and Couple Skills, which have sold more than four million copies combined. He received his PhD in clinical psychology from the California School of Professional Psychology, and specializes in the cognitive behavioral treatment of anxiety and depression. Catharine Sutker is a freelance writer living in the San Francisco Bay Area. She is the coauthor of The Self-Esteem Companion and The Self-Nourishment Companion.