For the fifth time since 1964, seismologists, other geophysicists, and geologists from the United States and Japan met in a joint seminar on earthquake prediction research. This time the emphasis was on the status of our understanding of earthquake precursors on the basis of theoretical and experimental studies. The Japanese research effort is now being carried out under the third 5-year program, started in 1974. The American scientists were able to report for the first time on results achieved under a formally established national program of prediction research, part of the Earthquake Hazards Reduction Program of the U.S. Geological Survey. Also for the first time, social scientists from the two nations were on hand to discuss their studies of the social and economic consequences of earthquake prediction.