Preface to Fouurth Edition : Control Valves are icreasingly vital component of modern manufacturing around the world. Properly selected and maintained control valves increase efficiency , safety, profitability , and ecologi. The Control valve Handbookhas beeb a primary reference since its first printing in 1965. This Fourth edition presents vitasl information on control valve performance and the latest technologies. * Chapter 1 offers an introduction to control valves including definitions for common control valve and instrumentation termininologi.