Popularization of science typically follows the lead of scientific research, conveying to lay audiences ideas and discoveries initially published in professional scientific literature and vetted by the expert community. The physicist George Gamow (1904–1968) did not respect this tradition, but promoted some of his most unorthodox scientific hypotheses as funny stories in his popular writings for non-specialists and teenagers, sometimes years before he dared to present them to the purview of academic peers in papers submitted to specialized research journals. Gamow’s proposal of the Big Bang cosmology—the theory that our universe started out in an explosive manner from a superhot and superdense state with thermonuclear reactions forming matter—was discussed by him initially in a series of non-serious articles and books, starting in 1938. Historians of cosmology recognize Gamow’s crucial contribution to the development of the Big Bang theory on the grounds of his subsequent professional publications but have not paid sufficient attention to his popular science writings and their role in changing our conception of the universe.