Robert S. Norris is the co-editor of the Nuclear Weapons Databook series, the five-volume definitive encyclopedia of the nuclear weapons of the United States, Soviet Union/Russia, Britain, France and China. He is also the author of Racing for the Bomb (2002), a biography of General Leslie R. Groves, the head of the Manhattan Project, which built the atomic bomb during World War II. Norris also co-authored the article on the history of nuclear weapons for the Encyclopedia Britannica. He is a senior research associate with the nuclear program of the Natural Resources Defense Council and director of NRDC's Nuclear Weapons Databook project.