The late Lyle Cummins lived with engines all his life. (His father, the late Clessie L. Cummins founded the diesel engine company that bears his name.) A mechanical engineer, Lyle Cummins spent fifteen years on engine-related projects and was granted five U.S. patents for inventions resulting from that work. Beginning with the initial patent applications through the contractual relations with licensees, his broad experience allows him to bring a unique perspective to bear on this subject, particularly in its relationship to engine history. Prior to his research on early engines he taught courses in mechanical design at a university school of engineering.