Less polished than Steve Reich's Music for 18 Musicians (1974), In C remains the most iconic example of early minimalism. As the liner notes for this digitally remastered 1968 Carnegie Hall recording say, the work is "a trip", its performers "a weird zoo".
Riley's semi-aleatoric score weaves a series of patterns around the piano's "pulse". Here it lasts 47 minutes, with 10 musicians playing 28 instruments, though the length and forces are infinitely variable. A fascinating document of the birth of a style that still dominates American music.