French mathematician and physicist who contributed to the development of the French atomic bomb and to the understanding of such diverse fields of research as semiconductors, seismology, and radio astronomy.

Rocard received doctorates in mathematics (1927) and physical science (1928) from the École Normale Supérieure (ENS) in Paris and took a job in the electronics industry. During World War II he worked with the resistance and supplied British scientific intelligence with vital information, including details on a new radio navigational beam station. For this assistance he was made a Commander of the Order of the British Empire (1946) and was later awarded the French Legion of Honour and the Order of Merit. After the war he returned to the ENS as head of the physics department, and in 1951 he was named to the French Atomic Energy Commission. His professional reputation suffered somewhat in later years when he concentrated on the scientific study of biomagnetism and dowsing. His son, Michel, served as French prime minister from 1988 to 1991.