Retinoic acid and its relatives, natural products of vitamin A metabolism, have been discovered to be critical ligands for key receptors of the steroid receptor superfamily, such as the retinoic acid receptor and the RXR receptor. Vitamins and Hormones has not had a review of this important fatsoluble vitamin for some time, and it seemed important not only to touch on the modern aspects of the retinoic acid receptor and its relatives but also of the roles of vitamin A in development and diVerentiation as well as its activity in certain tissues and in disease states
