Among basic human needs, food is foremost. Finding sufficient, affordable food is still the major concern of one in every five persons on earth. Rice is the basic staple for more than half of the world - and will continue to be well into the future. For this reason, the Interna­ tional Rice Research Institute (IRRI) has set the goal of improving the well-being of present and future generations of rice farmers and consumers, particularly those with low incomes. As we look toward the 21st century, several important issues cloud food security. World population is growing by almost 100 million people per year, and it is not likely to plateau before the end of the next century. This means that food demand will at least double, and may quadruple. The technologies of the Green Revolution have provided an unprecedented leap in annual rice production, enough to feed 600 million more people, but have had unforeseen social and environmental costs. Loss of genetic diversity and misuse of pesti­ cides endanger the sustainability of the Green Revolution. Soil ero­ sion, rural to urban popUlation migration, and increased competition for land and water between urban and agricultural sectors further threaten the sustainability of rice production. Finally, human activi­ ties may be changing the global climate. Any change in global climate is a potential challenge to the food security offuture generations. The world cannot afford to be unprepared.