A conductor enjoys the privilege of being able to reconsider his attitude to musical works over and over again. The composer Boulez adheres to the same maxim: of his own compositions he regards only very few as being finished; most of them are, to him, "work in progress." The first two pieces on this collage CD were actually withdrawn by Boulez after their premiere as he wished to think them over again. Later on, Polyphonie X (1951) in view of its extremely strict serial procedure appeared to him to be virtually "totalitarian" in its extreme and inflexible organization. Neither did Poésie pour pouvoir (1958) find favor in his eyes, in spite of the initial enthusiasm about the significance of the electronic contribution to the proceedings: "That way each work will have its own universe, its own structure and its own mode of generation on all levels." Tombeau à la mémoire du Prince Max Egon zu Fürstenberg (1959) at a later point became the final part of Pli selon pli. One of the few explicitly "finished" works is Structures II (1961), which compensates for this status by permitting the interpreters some liberty by aleatoric processes, ensuring that an original work is created by each individual performance. All tracks on this CD are world premiere recordings.