The book deals with linear integral equations, that is, equations involving an unknown function which appears under the integral sign. Such equations occur widely in diverse areas of applied mathematics, engineering sciences and physics. They offer a powerful technique for solving a variety of practical problems. One obvious reason for using the integral equations rather than differential equations is that all of the conditions specifying the initial value problems or boundary value problems for a differential equation can often be condensed into a single integral equation. In the case of partial differential equations, the dimension of the problem is reduced in this process so that, for example, a boundary value problem for a partial differential equation in two independent variables transform into an integral equation involving an unknown function of one independent variable.