This publication documents the origin and worldwide spread of maize from Mesoamerica, and describes the characterization, use, and conservation of maize genetic resources, including the crop's nearest wild relatives, teosinte and Tripsacum. Results of an international survey on the continued use of maize landraces in developing countries are reported, along with progress on the work of Latin American maize banks, in concert with CIMMYT, USAID, and USDA-NSSL, to regenerate their endangered holdings of maize landraces. An update is provided on collaborative research by CIMMYT and the French National Research Institute for Development Cooperation (ORSTOM) to transfer apomixis from Tripsacum to maize.