Women are twice as likely as men to experience protracted sadness, apathy, low self-esteem, and other symptoms of depression. How can we account for this sex difference? Several explanations have been proposed, some dating back many years. This book critically examines the evidence for each explanation in an attempt to discover what we do and do not know about sex differences in depression. It is a landmark review of the historical, theoretical and empirical approaches to sex differences in depression. Nolen-Hoeksema presents a fresh historical review, makes theoretical criticisms and offers clear and challenging avenues for future research and practical applications.