This practical manual presents a clear, illustrated introduction to automobile gas engines aimed at young readers. It breaks the engine down into individual parts—valves, piston, crankshaft, connecting rod, crankcase, carburetor, ignition and cooling systems—explaining how each functions and how they interact. It describes the four-stroke cycle and the two-cycle motor using simple analogies and step-by-step diagrams, and offers accessible explanations of operation, maintenance, and common mechanisms so readers can visualize and reason through engine action.