Visits by scientists and scholars then gradually increased, guided on the U.S. side by the nongovernmental National Academy of Sciences. Six years later, and presaging formal diplomatic relations in 1979, came the breakthrough science diplomacy mission of the President's Science Advisor Frank Press, accompanied by representatives of nearly every technical federal agency. That trip laid the groundwork for the formal Agreement on Cooperation in S&T, signed exactly 30 years ago this week by President Carter and the Chinese leader Deng Xiaoping.