Isaac Newton is considered one of the most important scientists in history. Even Albert Einstein said that Isaac Newton was the smartest person that ever lived. During his lifetime Newton developed the theory of gravity, the laws of motion (which became the basis for physics), a new type of mathematics called calculus, and made breakthroughs in the area of optics such as the reflecting telescope. In 1687 Newton published his most important work called the Philosophiae Naturalis Principia Mathematica (which means "Mathematical principals of Natural Philosophy"). In this work he described the three laws of motion as well as the law of universal gravity. This work would go down as one of the most important works in the history of science. It not only introduced the theory of gravity, but defined the principals of modern physics. Read the book to learn more about the surprising story of his life and work. "I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me." - Isaac Newton