In February 1963, not long after the Cuban Missile Crisis, David Lilienthal gave a series of lectures on nuclear weapons at Princeton University. As a leading US policymaker on atomic matters in the late 1940s (including as the first Chairman of the Atomic Energy Commission), Lilienthal had been instrumental in shaping early policy on the atomic bomb. Now, in the aftermath of the deepest nuclear crisis to envelop the United States, he conceded that his, and society’s, earlier thinking on the bomb had turned out to be incorrect. ‘We have been following a myth’, he exclaimed, ‘an illusion about the Atom’.