Marshall is the founder of the "Cambridge school". His main work, “Principles of Economic Science,” which appeared in 1890, was reprinted many times and for many decades served as the main textbook on economic theory not only in England, but also in a number of other Western countries. The central place in the book is occupied by the analysis of factors influencing price formation: demand, supply, production costs. It developed the theory of marginal value, introduced the concept of elasticity of demand, and distinguished three periods of equilibrium between supply and demand. Designed for researchers, teachers of social sciences, and specialists in the field of economic theories. The publication is carried out in three volumes.