A British mathematician and physicist who lived from 1643 - 1727. Newton made major advances in the studies of optics, mathematics, astronomy, and physics, most of which were published in his two major works, Opticks and Principia. Among other innovations, he constructed the first reflecting telescope (now known as a Newtonian style telescope), invented integral calculus, and postulated a Universal Law of Gravity. See also: Newtonian focus