Mathematical Theory of Huygens' Principle

From the Preface: 'The present monograph deals with the mathematical theory of Huygens' principle in optics and its application to the theory of diffraction. No attempt has been made to give a complete account of the various methods of solving special diffraction problems. [The authors] are concerned only with the general theory of the solution of the partial differential equations governing the propagation of light and [they] discuss some of the simpler diffraction problems merely as illustrative examples'.