This is the Fourth International Rice Genetics Symposium in the series of symposia held at IRRI every five years. The first, held in 1985, led to the birth of the Rice Genetics Cooperative (RGC). The RGC took the lead in organizing these symposia and greatly enhanced international collaboration. In the same year, the Rockefeller Foundation established its International Program on Rice Biotechnology, which has played a major role in advancing frontiers of knowledge on cellular and molecular genetics of rice, international collaboration, and human resource development. In the second symposium, a unified system of numbering rice chromosomes and linkage groups was adopted. The orientation of classical and molecular maps was one of the many highlights of the third symposium. The fourth symposium brought together 520 rice scientists from 32 countries and provided an excellent forum for scientists from developed and developing countries to share information on the latest advances in rice science and to develop collaborative research arrangements.