In 1962 the United States conducted its final atmospheric nuclear test series, Operation Dominic. The devices tested were designed and built by the Los Alamos Scientific Laboratory (LASL) and the Lawrence Radiation Laboratory (LRL). During the test series, LRL conducted four tests of a radically new design called the Ripple concept. Tests of the Ripple concept demonstrated performance characteristics that eclipse those of all nuclear weapons designed before or since. For numerous reasons discussed in the article, the Ripple concept was not pursued, but the technology it pioneered has been in continual development—for peaceful purposes—to this day. Until now, very little has been known about these tests and the concept behind them. This article, the result of a multiyear investigation, sheds light on the Ripple program for the first time, allowing for a largely complete account. Included are the origins of the concept and its designer, the technical characteristics, the significant role played by the geopolitical context, the test series in detail, and the cancellation and legacy of the program.