La Monte Thornton Young (born October 14, 1935) is an American composer, musician, and artist recognized as one of the first American minimalist composers and a central figure in post-war avant-garde music. He is best known for his exploration of sustained tones, beginning with his 1958 composition Trio for Strings. His works have called into question the nature and definition of music, most prominently in the text scores of his Compositions 1960. Despite having released very little recorded material throughout his career—much of it currently out of print—some sources have described him as "the most influential living composer today". The Observer wrote that his work has had "an utterly profound effect on the last half-century of music."