Alfred Whitford (Fred) Lerdahl (born March 10, 1943, in Madison, Wisconsin) is the Fritz Reiner Professor of Musical Composition at Columbia University, and a composer and music theorist best known for his work on pitch space and cognitive constraints on compositional systems or "musical grammar[s]." He has written many orchestral and chamber works, three of which were finalists for the Pulitzer Prize for Music: Time after Time in 2001, String Quartet No. 3 in 2010, and Arches in 2011.