Leonard S. Charlap, a former associate professor of mathematics in the School of Arts and Sciences, died on February 5 at home in Princeton, New Jersey. He was 84.

Dr. Charlap was born in Wilmington, Delaware and grew up in Penns Grove, New Jersey. He studied mathematics at the Massachusetts Institute of Technology and completed his PhD at Columbia University. In 1964, he joined the faculty of Penn’s mathematics department as an assistant professor, and in 1968, he was promoted to associate professor. From 1969 to 1970, he spent a year at Oxford University in the United Kingdom, then became a full professor at the State University of New York at Stony Brook upon his return. While at SUNY Stony Brook, Dr. Charlap received a National Science Foundation Award.

Dr. Charlap finished his career as a research staff member at the Institute for Defense Analyses’ Center for Communications Research (CCR) in Princeton, New Jersey. In Princeton, he was also a member of the Institute for Advanced Study during the 1960s and again in the 1990s, and was a member of the Center for Discrete Mathematics and Theoretical Computer Science at Rutgers University from 1990 to 1991. In 1986, Dr. Charlap published a renowned graduate textbook, Bieberbach Groups and Flat Manifolds. With his CCR colleague, David Robbins, he wrote a paper that has become the standard primer for those interested in beginning to study elliptic curves with an eye to algorithmic implementation. Dr. Charlap retired in 2000 and committed his life to his interest in classical music, visual art, the Philadelphia Eagles, his dogs, and current events. In his retirement, he frequently wrote letters to the editor of The New York Times, many of which were published.

He is survived by his two daughters, Jess and Emily Charlap; his brother, Richard Charlap; and his grandson, Rowan. No services will be held, as per Dr. Charlap’s wishes.