Grounded in decades of influential research, Perfectionism: A Relational Approach to Conceptualization, Assessment, and Treatment offers a comprehensive exploration of perfectionism: how it develops, its underlying mechanisms and psychological costs, and effective strategies for addressing it in psychotherapy. Authored by Paul L. Hewitt, this first edition delves into the origins of perfectionistic tendencies—rooted in early relational and developmental experiences—and explains how these tendencies make individuals vulnerable to a wide range of clinical problems. The book presents an integrative treatment approach that can be adapted to meet the unique needs of individual clients and includes a detailed group treatment model. State-of-the-art assessment tools are discussed, with resources available at the companion website. Throughout, vivid clinical illustrations bring the core ideas and techniques to life.