Lynn Arthur Steen (January 1, 1941 – June 21, 2015) was an American mathematician who was a professor of mathematics at St. Olaf College, Northfield, Minnesota, in the U.S. He wrote numerous books and articles on the teaching of mathematics. He was a past president of the Mathematics Association of America (MAA) and served as chairman of the Conference Board of the Mathematical Sciences. Source: Wikipedia (en)