This volume is a collection of all the problems in the Intemational Mathematical Olympiads (IMO) from the First (1959) through the Nine· teenth (1977) together with their solutions.
To explain how the problems are selected and the contests administered, I give a bit of the historical background. Various countries have conducted national mathematical contests for a long time. The Hungarian Eotvos Competition (begun in 1894, see NML vols. 11 and 12) is a famous example. In 1959 Rumania invited Hungary, Bulgaria, Poland, Czechoslovakia, the German Democratic Republic (G.D.R.) and the U.S.S.R. to participate in the First I.M.O. After a slow start the number of participating nations grew. Finland joined in 1965, Great Britain, France and Italy in 1967; and since then the number of participating nations grew rapidly, reaching twenty-one by 1977.