Johannes Kepler (German: [ˈkʰɛplɐ]; December 27, 1571 – November 15, 1630) was a German mathematician, astronomer, andastrologer. A key figure in the 17th century scientific revolution, he is best known for his laws of planetary motion, based on his worksAstronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy. These works also provided one of the foundations forIsaac Newton's theory of universal gravitation.