Dr Bennett traces the growing awareness of the importance and the significance of the concept of feedback in engineering and treats in detail the technical developments that contributed to his awareness. Beginning by studying the history of the control of prime movers, he examines in detail the 19th-century work on the stability problem. There follows an account of the development of steam and hydraulic servomechanisms and their application to the control of ships and aircraft.In the latter part of the book the development of electrical control systems from the arc lamp to the feedback amplifier is considered. The book ends with a brief outline of the theoretical work on circuit analysis which was to provide the background for the development that took place in the 1930s of techniques for the analysis of feedback systems.