Isaac Newton was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian who studied gravity. He is widely recognized as one of the most influential scientists of all time and as a key figure in the scientific revolution. He formulated the laws of motion and universal gravitation, which laid the foundation for classical mechanics. His book Philosophiæ Naturalis Principia Mathematica, published in 1687, is considered to be the most influential book in the history of science.