A major figure in 20th century music, Feldman was a pioneer of indeterminate music, a development associated with the experimental New York School of composers also including John Cage, Christian Wolff, and Earle Brown. Feldman's works are characterized by notational innovations which he developed to create his characteristic sound: rhythms which seem to be free and floating; pitch shadings which seem softly unfocussed; a generally quiet and slowly evolving music; recurring asymmetric patterns. His later works, after 1977, also begin to explore extremes of duration.
From Wikipedia
