The aim of the editors has been to create an up-to-date, comprehensive volume organized around five general sections: The Clinical Picture, Illnesses Related to Obsessive-Compulsive Disorder: Spectrum Disorders, Pathophysiology and Assessment, Treatment, and Patient and Clinic Management. To accomplish this, the editors have enlisted the help of 40 colleagues considered experts in their respective fields. For example, there are updated chapters by Steven Rasmussen and Jane Eisen ("The Epidemiology and Clinical Features of Obsessive-Compulsive Disorder"), Wayne Goodman and Lawrence Price ("Rating Scales for Obsessive-Compulsive Disorder"), John Alsobrook and David Pauls ("The Genetics of Obsessive-Compulsive Disorder"), and John March ("Cognitive Behavioral Psychotherapy for Pediatric Obsessive-Compulsive Disorder") and a new chapter by Randy Frost and Gail Steketee ("Hoarding: Clinical Aspects and Treatment Strategies"). Other well-known contributors include Katherine Phillips, Scott Rauch, and Michele Pato.