This book presents a new and original method for the solution of boundary value problems in
angles for second-order elliptic equations with constant coefficients and arbitrary boundary
operators. This method turns out to be applicable to many different areas of mathematical
physics in particular to diffraction problems in angles and to the study of trapped modes on a
sloping beach. Giving the reader the opportunity to master the techniques of the modern theory
of diffraction the book introduces methods of distributions complex Fourier transforms
pseudo-differential operators Riemann surfaces automorphic functions and the Riemann-Hilbert
problem. The book will be useful for students postgraduates and specialists interested in the
application of modern mathematics to wave propagation and diffraction problems.