This is a modern classic on the mathematical physics of wave propagation. It covers a wide range of problems with a common mathematical background, from solid state physics to propagation along electric lines, X-rays, gamma rays, certain optical reflections, electrical engineering, and wave mechanics of the spinning electron. The book discusses a general method and its applications, covering one-dimensional lattices and electric wave filters; complicated one-dimensional lattices and electrical analogues; energy velocity, flow, and characteristic impedance; two-dimensional lattices, and zones; three-dimensional lattices, and Brillouin zones, with rationalizations of systems of forbidden and permitted energy; Mathieu's equation, Hill's equation, Mathieu's functions, matrices, and propagation of waves along an electric line; and continuous electric lines. The mathematical physics of the transistor and similar semiconductor devices is considered. The treatment is outstandingly clear, making it most useful for intermediate and advanced students, research workers, teachers, and others concerned with aspects of mathematical physics. The book is well-received, with praise from the Acoustical Society, Science Progress, and Nobel Laureate Max Born. This is an unaltered, unabridged republication. It includes the author's preface, index, bibliography, and 131 illustrations. It is designed for long-term use with durable, high-quality paper and sewn-in signatures. The book opens flat for easy reference and has a permanent binding. It is available in paperbound format for $2.00.This is a modern classic on the mathematical physics of wave propagation. It covers a wide range of problems with a common mathematical background, from solid state physics to propagation along electric lines, X-rays, gamma rays, certain optical reflections, electrical engineering, and wave mechanics of the spinning electron. The book discusses a general method and its applications, covering one-dimensional lattices and electric wave filters; complicated one-dimensional lattices and electrical analogues; energy velocity, flow, and characteristic impedance; two-dimensional lattices, and zones; three-dimensional lattices, and Brillouin zones, with rationalizations of systems of forbidden and permitted energy; Mathieu's equation, Hill's equation, Mathieu's functions, matrices, and propagation of waves along an electric line; and continuous electric lines. The mathematical physics of the transistor and similar semiconductor devices is considered. The treatment is outstandingly clear, making it most useful for intermediate and advanced students, research workers, teachers, and others concerned with aspects of mathematical physics. The book is well-received, with praise from the Acoustical Society, Science Progress, and Nobel Laureate Max Born. This is an unaltered, unabridged republication. It includes the author's preface, index, bibliography, and 131 illustrations. It is designed for long-term use with durable, high-quality paper and sewn-in signatures. The book opens flat for easy reference and has a permanent binding. It is available in paperbound format for $2.00.