The International Years of the Quiet Sun (IQSY) is an enterprise of international scientific collaboration during the period of minimum sunspot activity lasting from 1 January 1964 to 31 December 1965. The scientific programmes to be carried out during the IQSY are planned to complement observations made during the International Geophysical Year (1 July 1957 to 31 December 1958) when the sun was last at its maximum activity. The co-ordination and administration of this undertaking is the responsibility of the IQSY Committee of the ComitC International de GCophysique (CIG-IQSY), an Inter-Union Committee set up by the International Council of Scientific Unions. The United Kingdom's contribution is organized by the Royal Society's British National Committee for Co-operation in Geophysics; it covers the following programme: