The Japanese physicist Sin-itiro Tomonaga (1906-1979) is best known for his fundamental contributions to quantum electrodynamics.

The oldest son of a philosopher and university professor, Sin-itiro Tomonaga was born on March 31, 1906, in Tokyo. After obtaining his degree from Kyoto University in 1929, he spent 3 years as a research student in Kajuro Tomaki's laboratory at the university and then became a research student under Yoshio Nishina in the Science Research Institute in Tokyo. Tomonaga remained there until 1940, with the exception of some time spent in 1939 at the University of Leipzig with Werner Heisenberg.

In 1940 Tomonaga married Rijo, by whom he had three children. In 1941, he became professor of physics at the Tokyo University of Science and Literature (which after the war became part of the Tokyo University of Education).

During the war years, while working in complete isolation from other physicists, Tomonaga made the contributions to quantum electrodynamics for which...