Since the fIrst edition of this book was published in the 1994, the theory of wave scattering from rough surfaces has continued to develop intensively. The community of researchers working in this area keeps growing, which provides justifIcation for issuing this second edition. In preparing the second edition, I was challenged by the problem of se lecting new material from the many important results obtained recently. Even tually, a new section was added to the central Chap. 6 of this book. This sec tion describes the operator expansion technique put forward by M. Milder, which conforms well...