Obsessive Compulsive Disorder (OCD) is currently the subject of considerable research, since recent epidemiological studies have suggested that the condition is more prevalent than was originally believed. This book offers a critical discussion of the most important theories that have been put forward to explain this disorder. The book includes behavioral/learning accounts (and cognitive-behavioral supplements of these), accounts based on Pavlovian personality theories (such as those by Eysenck, Gray, and Claridge), Pierre Janet's account, cybernetic approaches, psychodynamic approaches, Reed's "cognitive-structural" account, and biological approaches. Therapeutic approaches to the disorder are also considered, insofar as they are relevant to these theories.