After having taught the subject of integral equations for a number of years I
concluded that most potential texts are either too abstract, too old-fashioned,
or too specialized. The classical techniques yield rather precise information
regarding solvability of equations and existence and distribution of eigen￾values, but often require rather tedious and wearisome analysis. The functional
analytic techniques yield certain kinds of results quite expeditiously, but
often do not lead to the quantitative results provided by the classical tech￾niques. The aim of this book is to compromise between these approaches
to develop the most desirable features of each. The functional analytic
approach can be developed in a Banach space setting, but to keep the
treatment on a simpler level I have decided to restrict myself to Hubert
spaces.