John Norris Bahcall was an American astrophysicist, best known for his contributions to the solar neutrino problem, the development of the Hubble Space Telescope and for his leadership and development of the Institute for Advanced Study in Princeton. Bahcall was born on December 30, 1934, in Shreveport, Louisiana. He made fundamental contributions to the understanding of the elusive subatomic particles called neutrinos, which are emitted by the Sun. His work helped prove that the Sun and other stars produce their energy by means of thermonuclear reactions. During his career Bahcall published more than 500 scientific papers and articles that covered not only neutrino astronomy but also such subjects as quasars and dark matter. He was a tireless advocate for the Hubble Space Telescope and was a driving force in its development. From 1971 Bahcall served on the faculty of the Institute for Advanced Study, Princeton, N.J. In 1998, he received the National Medal Of Science. He graduated with an A.B. in Physics from Berkeley in 1956, obtained his M.S. in physics in 1957 from the University of Chicago and his Ph.D. in physics from Harvard in 1961. He became a research fellow in physics at Indiana University in 1960 and worked at the California Institute of Technology from 1962 to 1970, where he worked alongside Richard Feynman, Murray Gell-Mann, and William Fowler.