Only 15 years ago a conference on dietary fiber, let alone an international conference, would have been considered an extremely unlikely, and in fact an unthinkable, event. Yet in recent years a number of such conferences have taken place at the international level and in different parts of the world; the conference of which the present volume is an outgrowth is the second to have been held in Washington, D. C. This extraordinary development of interest in a hitherto largely neglected component of diet has been reflected by a veritable explosion of scientific literature, with published articles increasing 40-fold, from around ten to over 400 per year, within the decade 1968-1978. Not only has the growth of interest in and knowledge of fiber made it perhaps the most rapidly developing aspect of nutritional science in recent history if not in all time, but epidemiologic studies relating fiber intake to disease patterns, subsequently broadened to include other food components, have been largely responsible for the current concept of diseases characteristic of modern Western culture and lifestyle. The potential importance of this realization is forcefully underlined by the considered judgment of Thomas MacKeown, epidemiologist and medical historian of Birmingham University, England.