The genesis of Pierre Boulez’s only string quartet Livre pour quatuor—begun by the composer in the late 1940s and left unfinished at the time of his death—resembles a veritable never­ending story. In 2018, Philippe Manoury, one of today’s leading French composers and a close artistic associate of Boulez, completed the fragment of the fourth movement based on the extant sketches. The West-Eastern Divan Ensemble per­forms Manoury’s version, which had its world premiere at the Pierre Boulez Saal, juxtaposing it with Mozart’s Clarinet Quintet and Schubert’s late String Quintet.