This document summarizes information about valve mechanisms in internal combustion engines. It discusses the basic operation of valves using camshafts and the components involved like cam lobes, followers, push rods and rocker arms. It also introduces future camless valve technologies that would be electrically controlled. The document outlines the main types of valves used in 2-stroke and 4-stroke engines and lists the advantages of more advanced valve mechanisms as better fuel efficiency and performance, though they are more complex and expensive.