Profoundly influential mathematician and natural scientist. His writings were voluminous, with his most important publications being Philosophiæ Naturalis Principia Mathematica (1687), which included his formulation of the law of universal gravitation, Opticks: or, A Treatise of the Reflexions, Refractions, Inflexions and Colours of Light (1704), and Arithmetica Universalis (1707).