PREFACE T IS the purpose of these two Manuals on BASIC SYNCHROS AND SERVOMECHANISMS to describe and illustrate, in the simplest possible way, the fundamental characteristics of two groups of devices which are not only used in many types of military equipment, but which are also essential components in what will assuredly be one of the most revolutionary industrial techniques of the second half of the 20th century. Automatic process control-automation, to use its more popular name-is an outgrowth of the technical advances made in military equipment during the Second World War. It is far more than the mere regrouping of existing machines, which is what many people believe it to be. It is a radically new concept. The idea of mechanization implies a set of mechanical devices carrying out a series of motions-pre-determined, accurate, and continuous as long as power is supplied-but lacking any ability to modify their own behaviour if conditions begin to vary. Automation, on the other hand,...