Large Professor

William Paul Mitchell (born March 21, 1972), better known by the stage name of Large Professor (also Extra P. and Large Pro), is an American rapper and record producer. Based in New York City, he is a founding member of the underground hip-hop group Main Source, and is credited with having discovered and mentored fellow New York City-based rapper Nas. About.com ranked Large Professor at No. 13 on its Top 25 Hip-Hop Producers list.