What I had in mind when I started planning this book was a collection of scholarly essays, each dealing with the problem of obsesity from a particular point of view, which I hoped would be of value to all those working in the field, either as researchers or as therapists. I approached my task in the spirit of an art collector. Such a person must soon recognise that he or she can never, unless possessed of quite extraordinary powers, (and I certainly am not), gather unto himself all the known examples of the works he wishes to collect. Rather he must select, picking out those items which he believes to be most important in the area he is covering. That is what I have tried to do in this book. As with an art collection, an editor of a series of essays must select both for content and for author. I realise that any such selection is bound to be some- what arbitrary, but I have tried to include those topics related to obesity which I consider to be, not only the most relevant, but also those in which the most significant theoretical and practical advances are currently being made. The first four of the seven contributions included in the book are concerned with pathogenesis, and the remaining three with management. The first chapter, by Dr. John Garrow, is an overall review of the metabolic influences on body weight as a whole.