Johannes Kepler (/ ˈ k ɛ p l ər /; German: [joˈhanəs ˈkɛplɐ, -nɛs -] (); 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of planetary motion, and his books Astronomia nova, Harmonice Mundi, and Epitome …