The book "The Theory of Existence of General Equilibrium: In the History of Mathematical Economics" focuses on the nature of different paradigms involved in the development of the existence of general equilibrium during 1838-1976. It examines the factors which led the general equilibrium theorists to develop the model of existence of general equilibrium: the individuals responsible for identifying the problem associated with the earlier general equilibrium theory; the link between the earlier and the modern theory of the existence of equilibrium: the individual or group who developed the first existence proof; the contributions of the modern existence theorists of general equilibrium; the approach which finally did emerge. This book reveals how the proofs of existence of competitive equilibrium system have been modified by developments of appropriate mathematical techniques.