Paul Keres was an Estonian chess grandmaster and chess writer. He was among the world's top players from the mid-1930s to the mid-1960s, and narrowly missed a chance at a World Chess Championship match on five occasions. As Estonia was repeatedly invaded and occupied during World War II, Keres was forced by the circumstances to represent the Soviet Union and Nazi Germany (1941–44) in international tournaments.

Grandmaster (GM) is a title awarded to chess players by the world chess organization FIDE. Apart from World Champion, Grandmaster is the highest title a chess player can attain. Once achieved, the title is held for life, though exceptionally the title can be revoked for cheating.