In the past five years, a surprising and intense resurgence in interest in vitamins and other micronutrients and their role in health and dis ease has occurred. The recognition has emerged that vitamins not only are essential for life ·in that severe nutritional deficiencies occur in their absence, but that these compounds may also serve as natural inhibitors of cancer. Synthetic alterations of the basic vitamin A mole cule have also resulted in the production of compounds that are more potent as anticancer agents than the natural substance and may have substantial therapeutic activity as well. Whether other vita mins can be changed or altered to produce a better anticancer effect than the native compound has been little explored to date, but should be a fruitful pursuit for future study. In our concluding remarks to the First International Conference in 1982, we speculated that rapid advances in our understanding of vi tamins would occur in the next few years and that large-scale inter vention trials of vitamins as preventive agents in defined human pop ulations would be started. This anticipated generation of data on vitamins and their interactions has proceeded rapidly and the impor tance of interactions between vitamins and other micronutrients in the prevention setting has become better appreciated. Currently, more than 25 intervention trials with a variety of target populations using vitamins and other micronutrients have been started, but it re mains too early for meaningful analysis of the results to date.