The book is devoted to the role of mathematics in human knowledge of the world. On the example of creative biographies of three prominent Russian mathematicians of the twentieth century - A. N. Kolmogorov, S. L. Sobolev and A. N. Tikhonov - the achievements of modern mathematics are popularly described. The book will be of interest to students studying the course of higher mathematics, teachers and teachers of mathematics, everyone who is interested in this ancient science.