Trained as a theoretical physicist, Edward Teller became a leading authority on nuclear physics during the 1930s and was involved with the Manhattan Project during World War II. He was an early advocate of thermonuclear weapons, which are many times more powerful than the atomic bomb, and he is best known for the leading role he played in the development of the hydrogen bomb between 1949 and 1951. Beginning in the 1940s, Teller figured prominently in policy discussions about America's nuclear arsenal, advising government officials at the highest levels and even testifying against J. Robert Oppenheimer at a Congressional hearing during the McCarthy era. By the 1980s, a lifetime of advising politicians had given him a network of political contacts that included a friendship with President Ronald Reagan. Teller was instrumental in convincing Reagan that a system could be developed to shoot down incoming ballistic missiles. Many consider him responsible...