The book of the outstanding American physicist D. A. Wheeler is devoted to the elementary presentation of geometrodynamics - the embodiment of Einstein's dream "to reduce all physics to geometry." The author begins with the elementary concepts of dynamics and the particular theory of relativity, then moves on to metrics and its relationship with mass distribution, and then to topology and "dynamic geometry," geometrodynamics. He considers in detail the simplest problem of geometrodynamics - gravitational collapse - and finally introduces the reader to the application of the presented ideas to the problem of the structure of elementary particles. The applications contain the necessary information about the "arena of action" of geometrodynamics - superspace and its properties. The book will be of great interest to physicists, astronomers, mathematicians - both specialists and senior students and graduate students.