Sheldon Lee Glashow grew up in New York City and graduated from Bronx High School of Science, where he and Steven Weinberg were classmates. Glashow received his Ph.D. in 1958 from Harvard University. While a student at Harvard, Glashow studied with Julian Schwinger, a pioneer of quantum electrodynamics who had become interested in the weak interaction and its possible connection with the electromagnetic interaction. In 1961 Glashow took the first step in unifying these interactions. It was finally accomplished in 1967 by Steven Weinberg and Abdus Salam, and in 1979 all three received a Nobel Prize in physics for developing a theory that mathematically and theoretically unifies the weak force and electromagnetic force of the atomic nucleus. In 1970 Glashow and two collaborators proposed the existence of the charm quark; several years later, physicists discovered particles that contain charm quarks and antiquarks. The grand unified theory that links the strong and electroweak interactions, which Glashow and Howard Georgi devised in 1974, accounts for many otherwise unexplained observations. Since 1979 Glashow has also been on the Harvard faculty, where he occupied the Eugene Higgins Chair of Physics.