Fowler, William Alfred (1911-1995), an American nuclear astrophysicist, developed a theory of the evolution and death of stars. For his work, Fowler was one of two recipients of the 1983 Nobel Prize in physics. He shared the prize with the American physicist Subrahmanyan Chandrasekhar, who also worked on processes of stellar evolution. Fowler and his colleagues at the California Institute of Technology (Caltech) are considered the founders of the field of nuclear astrophysics.

According to Fowler's theory, during the evolution of stars, lighter elements are continuously joined together to form heavier elements. The reactions involved produce light and heat. He suggested that supernova (explosion of an unstable star) produces the final synthesis of the heaviest elements. Fowler's theory, developed during the 1950's, explained the formation of all chemical elements in the universe. Later research confirmed the theory.

Fowler was born in Pittsburgh, Pennsylvania. He studied ceramic engineering at Ohio State University, and during the course he developed an interest in physics. After graduating, Fowler went on to Caltech, where he received his Ph.D. degree in nuclear physics in 1936. He then taught physics and carried out research at the W. K. Kellogg Radiation Laboratory at Caltech until his retirement in 1982.

Besides the Nobel Prize, Fowler's honors included the Presidential Medal of Merit (1948), the Apollo Achievement Award (1969), the National Medal of Science (1974), the Bruce Gold Medal (1979), and the French Légion d'Honneur (1989). He received honorary doctorates from several institutions, including the University of Chicago and the Observatoire de Paris. He was a member of the National Academy of Sciences and served as president of the American Physical Society in 1976.

Fowler married Ardiane Foy Olmsted in 1940. They had two daughters. Olmsted died in 1988. Fowler married Mary Dutcher in 1989.