The International Years of the Quiet Sun, a two‐year period of international scientific cooperation in studying the relationship between the sun and the earth and its environment during a period of minimum solar activity, began on January 1 and will end next year on December 31. Scientists from sixty‐four countries are participating. The IQSY program complements that of the International Geophysical Year in 1957 and 1958, when the sun was at its most active. In both astronomy and the earth sciences, areas of study affected by solar events will be better understood after a comparison of data obtained during periods of both minimum and maximum solar activity.