First published in 1992. This book aims to bring the reader up to date on current research, theory and conceptualisations of the depressive disorders. It offers a new perspective derived from evolution theory and argues for the adoption of the biopsycho- social model. Part I explores the major distinctions between all types of depression, including discussion of seasonal affective disorder, postnatal depression and depression in children. The chapter on epidemiology covers issues of prevalence, relapse, long term outcome and chronic depression. The relationship between depression and various approaches to personality and personality disorder are also covered in detail. Part II offers an overview of evolution theory and its application to depression. Special attention is given to social comparison, submissive behaviour, sense of inferiority, helplessness and weakness, shame, guilt, anger and resentment, and envy in depression. These are seen to relate to two basic, central human concerns, social power and belonging. This approach offers a coherent account of why these various aspects of functioning are often part of depressive experience. Part III covers the major theories of depression, including psychoanalytic, object relations, archetype, mentality, attachment, self psychology, incentive, cognitive, behavioural and social. Theories are compared and contrasted, highlighting controversies, weaknesses and strengths, and where cross fertilisation of ideas may be beneficial. The final chapter outlines why simple theories of aetiology are inadequate and explores the role of culture and social relationships as elicitors of many forms of depression.