The book of one of the leading theoretical physicists of the first half of the 20th century and the famous popularizer of science, George (George) Gamow, tells about the work of three giants of scientific thought: Galileo Galilei with his systematic experiments on the free fall of bodies; Isaac Newton, who introduced the concept of gravitation as some universal force and mathematically formulated the law of universal gravitation; as well as Albert Einstein, who considered gravity as a kind of curvature in a four-dimensional continuum of space-time.