Johann Kepler, better known as Johannes Kepler, was a German mathematician, astronomer, and astrologer who is a key figure in the scientific revolution. Kepler is best known for his laws of planetary motion, which provided one of the foundations for Isaac Newton's theory of universal gravitation. His work helped to change the understanding of the cosmos, showing that the planets orbit the sun in elliptical paths rather than perfect circles. Kepler's contributions to science, particularly in astronomy and optics, have made him one of the most influential figures in the history of science.