This book has been designed, as its title implies, as a practical book for medical practitioners, although it should be of interest to medical students and nutritionists. It attempts to provide essential information about this important group of substances rather than be an all embracing monograph on the subject. For this reason biochemical and physiological considerations have been kept to a minimum, and aspects of animal disorders and animal husbandry have not been considered. The material is often presented in a rather dogmatic fashion and, with rare exceptions, references are not included since this makes reading more difficult. The exceptions, where references are provided, are the therapeutic claims, and the series of recent studies which have indicated that vitamin deficiencies are still widely present among certain groups of the population of many industrially developed countries. To add to this reference list there is a reading list which has been selected to give key books, reviews with extensive bibliography and important articles over the past 10 years. From this reading list it is possible to trace most of the literature on the vitamins since they were first described over half a century ago.