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The Dartmouth
July 22, 2025 | Latest Issue
The Dartmouth

Professor, former dean dies

Leonard M. Rieser, a former Dean of the Faculty and Provost of the College and a participant in the Manhattan Project, died Dec. 15 of cancer at the Dartmouth-Hitchcock Medical Center. He was 76.

Rieser spent 46 years as a faculty member and administrator at Dartmouth, beginning as an instructor in physics in 1952.

"Certainly, he ranks as one of the key half-dozen people who have reshaped and strengthened Dartmouth in the last half of the twentieth century," College President James Wright said in a statement in December.

Prior to his employment by the College, Rieser served with the Army on the Manhattan Project, which led to the creation of the atomic bomb. Rieser worked at the project's Metallurgical Laboratory at the University of Chicago and subsequently at the Los Alamos Laboratory in New Mexico.

At Los Alamos, Rieser witnessed the first explosion of an atomic bomb.

Rieser gained national recognition in his former positions as president and chairman of the board of the American Association for the Advancement of Science, and Chairman of the Board of the Bulletin of Atomic Scientists.

In the latter, Rieser appeared in many news photographs setting the hands of the "Doomsday Clock," a tool used by the Bulletin of Atomic Scientists to portray the threat of nuclear war and the importance of finding peaceful solutions to international hostility.

Born May 18, 1922, Rieser grew up in Chicago. His college career began at Dartmouth, where he enrolled as a member of the Class of 1944. After two years at the College, he transferred to the University of Chicago to pursue his scientific interests.

Rieser earned his bachelor's degree in physics in December 1943 from Chicago and immediately began work for the Army. After earning an honorable discharge in 1946, Rieser attended Stanford University, where he earned a doctorate in physics in 1952.

Rieser returned to Dartmouth in 1952 as a physics professor. He began his administrative work concurrently with his teaching when he served as chair of the physics department from 1957 to 1959 and deputy provost for the sciences from 1959 to 1964.

In 1964, Rieser became deputy provost of the College. He then became dean of the faculty and ultimately College provost.

In 1977 Rieser became the first chairman of the Montgomery Endowment at Dartmouth, a funding program that brings prominent professionals and academics to campus for periods as long as one year. In 1984, he was appointed the first director of the John Sloan Dickey Center for International Understanding at Dartmouth.

Rieser served on a number of other committees and associations in and out of Dartmouth, including his position as President of the Board of Trustees of the Montshire Museum of Science in Norwich, Vt., which he held until his death.

Rieser is survived by his wife Rosemary Rieser, two brothers, his four children and three grandchildren.