The purpose of this book is to acknowledge the universality of depression, to throw some light on those aspects of depression which are neglected in the more conventional treatments of the subject and also to attempt to provide a synthesis between the biological and socio-environmental factors which lead to the onset of depression and modify its course. A book devoted to depression has the advantage that it has the space at its disposal to explain and clarify concepts and promising ideas that a chapter in even a comprehensive textbook does not have. A single author writing about all the relevant aspects of a subject brings with him the merit of uniformity, continuity and lack of repetition. He is also more fallible in some areas than others, which finds an exact parallel in the experience of clinicians in their practice. A multi-author, multi-specialist work portrays an air of omniscience and omnicompetence which many clinicians find dispiriting. It is likely a considerable number of practising clinicians will have a greater knowledge and experience in some areas of the subject of this book. than I have and will feel emboldened to approach others. The entire work is informed by historical considerations. The lesson of history is to be open-minded and not to judge too harshly those that have gone before.