This classic book derives from a lecture course Vladimir Gribov, who was one of the founding fathers of high-energy elementary particle physics, delivered to graduate students in the 1970's. It thus provides today's graduate students and researchers with the opportunity to learn from the teaching of one of the twentieth-century's greatest physicists. Its content is still deeply relevant to modern research, for example exploring properties of the relativistic theory of hadron interactions in a domain of peripheral collisions and large distances that quantum chromodynamics has barely approached. It covers a combination of topics not treated elsewhere, while remaining self-contained and accessible at a graduate level.