Sir Isaac Newton's work was the capstone of this evolving chain of science. He integrated Kepler's laws of planetary motion and Galileo's forays into the laws of gravity into a comprehensive understanding of the organization of the universe according to the law of universal gravitation. Newton's Principia, in which he lays out this comprehensive system of organization and develops the mathematical field of calculus, is seen as the key which unlocked the mysteries of the universe, the climax of the strivings of all of the Scientists of the Scientific Revolution.