Mathematics has long served as a reliable help for people in commercial calculations, helped navigators determine the position of the ship at sea, surveyors - measure land plots, astronomers - draw up calendars. The famous Dutch mathematician and teacher Hans Freudenthal vividly and fascinatingly talks about the development of mathematics, about its place in modern science and the life of each of us. His book will be read with great interest and benefit by people of all ages, professions and hobbies.