Johannes Kepler was a German mathematician and astronomer best known for his laws of planetary motion. His work laid the foundation for modern astronomy and helped to confirm the heliocentric model proposed by Nicolaus Copernicus. Kepler's laws describe how planets move in elliptical orbits around the sun, revolutionizing our understanding of the solar system. In addition to his contributions to astronomy, Kepler was also a pioneer in the field of optics. He discovered the principles of how lenses work, which later influenced the development of telescopes. His legacy continues to impact science and mathematics today.