The idea of a symposium devoted to the contemporary knowledge of the world of Copernicus - the planetary system - to commemorate the 500th anniversary of his birth, came during the XIV General Assembly of IAU in Brighton. The Executive Committee has approved it in the program of the Extraordinary (Copernicus) General Assembly ofIAU in Poland in 1973. The IAU Symposium No 65 (Copernicus Symposium IV) on the 'Exploration of the Planetary System' was held in Copernicus' native town - Torun, Poland, from 5th to 8th September, 1973 under the auspices of Commissions 16 (Physical Study of Planets...