From the publisher The book is devoted to the main problems of modern physics. Its author is a foreign member of the USSR Academy of Sciences, a world famous scientist who wrote a painful number of deep scientific papers on field theory, electrodynamics, nuclear physics, high-energy physics and elementary particles. Three of his works were milestones in the development of physics. The essays included in the book address fundamental problems of a general physical nature, for example, the question of quality and quantity in quantum theory, and narrower issues, for example, parity violation and nuclear models. In addition, the book contains a number of review articles and several essays on sociological and humanitarian issues, the development of physics. The book is designed for a wide range of readers.