Stockhausen's revolutionary sonic experiments and Pierre Boulez's groundbreaking work in electronic music, aleatory (controlled chance) in serial composition, La Marteau Sans Maitre, come together. The Stockhausen pieces include his first foray into musique concrete, Etude Concrete ; his four Klaviersteck movements, and his Zeitmasse for Five Woodwinds. The Robert Craft performances here have been out of print for decades!