The document discusses the engine head of an internal combustion engine. It describes the engine head as the component that seals the top of the cylinder and includes passages for air/fuel intake and exhaust. The main components of the engine head are identified as the head gasket, intake and exhaust ports, valves, combustion chamber, spark plugs, camshaft, and valve springs. Flat head, overhead valve, and overhead camshaft cylinder heads are the main types discussed. The functions of the engine head are to mount various components, seal the combustion chamber, and transmit mechanical power.