Most of this analysis, however, has focused on the past performance and future prospects for cereals and livestock. This paper analyzes recent trends in and alternative projections of the supply, demand, and trade for roots and tubers (R and T). In doing so, it seeks to provide a clearer vision of the contribution that these crops can make to the food systems of developing countries through the year 2020. A key objective of this paper is to clarify and, as much as possible, to quantify the complexity and magnitude of that contribution.