Depression is a major cause of morbidity throughout the world. Given that between 8 and 12% of the population (in most countries) will suffer from depression at some point in their lives, it is clearly a significant public health problem. As our knowledge of this illness has expanded in recent years, it has become clear that depression can no longer be viewed as a simple disorder of the brain. It has to be seen as a series of behavioural and biological changes that span mind, brain, genes, and body--indeed, affecting both psychological and physical health. This book brings together world leaders in research on depression to discuss, for the first time, in an interdisciplinary setting, both classical and innovative ideas to understand this devastating disorder. It presents neurobiological, psyschological, genetic, and evolutionary models with a particular emphasis on the mechanisms linking the brain to the endocrine and the immune systems, and therefore, linking depression to physical health. Opening with a powerful, personal account of depression that conveys something of the all-consuming, debilitating nature of this illness, the book then presents cutting-edge research from those at the frontier of work in this area. The book is valuable for all those in the brain sciences seeking a state-of-the-art review of this global problem.