This volume opens with an overview of the diagnosis and assessment of OCD in adults and delineates an evidence-based conceptual framework for understanding the development, maintenance, and treatment of obsessions and compulsions. The core of the book that follows is a highly practical treatment manual, based on decades of scientific research and clinical refinement, packed with helpful clinical pearls, therapist-patient dialogues, illustrative case vignettes, sample forms and handouts. State-of-the-art strategies for enhancing exposure therapy using inhibitory learning, ACT, and couples-based approaches are described. Readers are also equipped with skills for tailoring treatment to patients with different types of OCD symptoms (e.g., contamination, unacceptable thoughts, challenging presentations such as mental rituals) and for addressing common obstacles to treatment. The book is an essential resource for anyone providing services for individuals with anxiety disorders.