Sir Isaac Newton was an English physicist, mathematician, astronomer, alchemist, inventor and natural philosopher who is generally regarded as one of the most influential scientists in history.

Newton wrote the Philosophiae Naturalis Principia Mathematica wherein he described universal gravitation and the three laws of motion, laying the groundwork for classical mechanics. By deriving Kepler's laws of planetary motion from this system, he was the first to show that the motion of bodies on Earth and of celestial bodies are governed by the same set of natural laws. The unifying and deterministic power of his laws was integral to the scientific revolution and the advancement of heliocentrism.

Among other scientific discoveries, Newton realized that the spectrum of colours observed when white light passes through a prism is inherent in the white light and not added by the prism (as Roger Bacon had claimed in the 13th century), and notably argued that light is composed of particles. He also developed a law of cooling, describing the rate of cooling of objects when exposed to air. He enunciated the principles of conservation of momentum and angular momentum. Finally, he studied the speed of sound in air, and voiced a theory of the origin of stars.

Newton shares credit with Gottfried Leibniz for the development of integral and differential calculus, which he used to formulate his physical laws. He also made contributions to other areas of mathematics, having derived the binomial theorem in its entirety. The mathematician and mathematical physicist Joseph Louis Lagrange (1736–1813), said that "Newton was the greatest genius that ever existed and the most fortunate, for we cannot find more than once a system of the world to establish."

Newton was born in Woolsthorpe-by-Colsterworth (at Woolsthorpe Manor), a hamlet in the county of Lincolnshire.

Newton began his schooling in the village schools and was later sent to Grantham Grammar School where he became the top boy in the school.

In June 1661 he matriculated to Trinity College, Cambridge.Soon after Newton had obtained his degree in 1665.

From 1670 to 1672 he lectured on optics. During this period he investigated the refraction of light, demonstrating that a prism could decompose white light into a spectrum of colours, and that a lens and a second prism could recompose the multicoloured spectrum into white light.

In 1665 the University closed down as a precaution against the Great Plague. For the next 18 months Newton worked at home on calculus, optics and law of gravitation.

He was elected Lucasian professor of mathematics in 1669.

Newton is generally credited with the binomial theorem, an essential step toward the development of modern analysis. Newton and Gottfried Leibniz developed the calculus independently, using different notations.
He concluded that any refracting telescope would suffer from the dispersion of light into colours, and invented a reflecting telescope (today, known as a Newtonian telescope). In 1671 the Royal Society asked for a demonstration of his reflecting telescope.

The Philosophiae Naturalis Principia Mathematica (now known as the Principia) was published on 5 July 16871 with encouragement and financial help from Edmond Halley. In this work Newton stated the three universal laws of motion that were not to be improved upon for more than two hundred years. He used the Latin word gravitas (weight) for the force that would become known as gravity, and defined the law of universal gravitation. In the same work he presented the first analytical determination, based on Boyle's law, of the speed of sound in air.