The International Mathematical Olympiad has been held annually, since 1959; the U.S. began participating in 1974, when the Sixteenth International Olympiad was held in Erfurt, G.D.R

In 1974 and 1975, the National Science Foundation funded a three week summer training session with murray S. Klamkin of the University of Alberta, and Samuel L. Greitzer of Rutgers University as the U.S. teams' coaches. Summer training sessions have been funded since 1976 by grants from the Army research Office and Office of Naval Research. The first time the U.S.A. participated, we scored second among the eighteen participating nations. The U.S. team usually places among the top three and in 1977, 1981, and 1986 was first. IMO 81' hosted by the U.S.A was the first to held outside Europe.

Members of the U.S. team are selected from 75-100 top scores on the Annual High School Examination (See NML vols. 5, 17, 25, 29) and the American Invitational Mathematics Examination by subsequent competition in the U.S. Mathematical Olympiad. NML Volume 27 offers a compilation of the Internatianl Mathematical Olympiads from 1959-1977.

In this volume the dedicated coach and problemist, Murray S. Klamkin, has compiled all of the IMO problems from the twentieth (1978) through the 27th (1985) IMO and their solutions. in this book he has also included forty additional problems which had been submitted to the Olympiad Committee.

The problems are solvable by methods accessible to secondary school students in most nations, but insight and ingenuity are often required. a chronological examination of the questions throws some light on the changes and trends in secondary school mathematics curricula.