Motoo (pronounced "moe-toe") Kimura was an evolutionary biologist. Coming to the United States by boat from Japan, he made one of his first great contributions to biology during that voyage in the form of a solution to the diffusion approximation of genic evolution. Unfortunately, he was too late to study under his idol Sewall Wright who was about to retire from biology. He eventually came to study with James Crow, embarking on a stunning career. Kimura is most widely remembered for his development of the neutral theory of molecular evolution, in which neutral mutations are pervasive and evolutionarily significant.