Robert Jay Finkelstein (March 26, 1916 – August 27, 2020) was an American theoretical physicist, specializing in elementary particle physics. Finkelstein was born in Pittsfield, Massachusetts in March 1916. After graduation from Pittsfield High School, he matriculated in 1933 at Dartmouth College, graduating there as salutatorian in the class of 1937. He received his Ph.D. in 1941 from Harvard University with dissertation The Energy Levels of Chrome Alum. II. Magnetic Susceptibility of Cerium Ethylsulfate under the supervision of John Hasbrouck Van Vleck. After completing his last doctoral examination, he went to Washington, DC to join Francis Bitter’s research group in the Navy Department. Finkelstein worked briefly with an operational research group that included Marshall Stone and Josep