John Coolidge Adams (born February 15, 1947) is an American composer of classical music and opera, with strong roots in minimalism. His works include Harmonielehre (1985), Short Ride in a Fast Machine (1986), On the Transmigration of Souls (2002), a choral piece commemorating the victims of the September 11, 2001 attacks (for which he won the Pulitzer Prize for Music in 2003), and Shaker Loops (1978), a minimalist four-movement work for strings.