The earliest speculations about nuclear power—first, about nuclear fusion— followed soon after the publication of Albert Einstein’s special theory of relativity. A story related by Edward Teller tells of the young George Gamow’s being offered, in 1929, the nightly use of the full electric power grid of Leningrad if he would undertake to create in the laboratory the fusion energy that Atkinson and Houtermans were claiming to be sufficient to explain stars (Teller, 1981). Then, when fission was discovered in 1939, fusion took a back seat as the more readily exploitable fission process forged ahead, culminating in the first fission power reactors in the 1950s.