Donat G. Wentzel (June 25, 1934 – February 20, 2013) was an American astrophysicist, best known as astronomy educator of undergraduates, graduates, and young researchers.A graduate of the University of Chicago, he established himself in plasma astrophysics, working on cosmic magnetism and electrical currents flowing both between the stars and on the Sun. His outstanding contribution was on Alfven waves driven by cosmic rays and the emission processes of solar flares at radio waves. His book on the “Restless Sun,” written for undergraduates, was named Book of the Year by the Astronomical Society of the Pacific in 1989. Wentzel received 2003 the George Van Biesbroeck Prize. His nomination reads: "For outstanding and sustained contributions during three decades to astronomy education in this