List of Famous people who died at 90

Joy Paul Guilford was an American psychologist best remembered for his psychometric study of human intelligence, including the distinction between convergent and divergent production.

Giuseppe Caprio, was an Italian cardinal of the Roman Catholic Church. He held the post of President of the Prefecture for the Economic Affairs of the Holy See before he retired in 1990. He had been the internuncio, then pro-nuncio, to China from 1959–1967, and the pro-nuncio to India from 1967–1969.

Leo Zippin was an American mathematician. He is best known for solving Hilbert's Fifth Problem with Deane Montgomery and Andrew M. Gleason in 1952.

Alexander Alexandrovich Mikulin was a Soviet Russian aircraft engine designer and chief designer in the Mikulin OKB. His achievements include the first Soviet liquid-cooled aircraft piston engine, the Mikulin AM-34, and the Mikulin AM-3 turbojet engine for the Soviet Union's first jet airliner, the Tupolev Tu-104. Mikulin also took part in the Tsar Tank project.

Kenneth Ross MacKenzie together with Dale R. Corson and Emilio Segrè, synthesized the element astatine, in 1940. MacKenzie received his PhD under Ernest Lawrence at Lawrence Livermore National Laboratory. Lawrence, MacKenzie, and their colleagues devised the first cyclotron. He was a professor of physics at UCLA, where he and Reg Richardson built UCLA's first cyclotron and later a bevatron. MacKenzie devised MacKenzie buckets which are plasma sources created by lining vacuum chamber walls with permanent magnets of alternating polarity to suppress plasma electron losses, that are widely used to this day. He later traveled around the world, helping to troubleshoot various country's cyclotron problems. Later in life, he studied plasma physics and dark matter.

Major Sir Jocelyn Morton Lucas, 4th Baronet, was a British Conservative Party politician. He was elected as the Member of Parliament for Portsmouth South in a by-election in 1939 and held the seat until he retired at the 1966 general election. Prior to his election he had been the Portsmouth District Officer for Sir Oswald Mosley's British Union of Fascists.

Arthur Francis "Bud" Buddington was an American geologist. Born in Wilmington, Delaware, he grew up there and in West Mystic, Connecticut. He was educated at Brown University and Princeton University.