During his lifetime, “work in progress” became a familiar label in Pierre Boulez’s list of compositions, as many of his pieces were repeatedly revised and elaborated over the course of his career. Most did eventually reach what Boulez regarded as a definitive state, but the ones that remained in compositional limbo the longest was his only string quartet, which he had begun to plan in 1948 (the year of his Second Piano Sonata and the cantata Le Soleil des Eaux). For many years, only five of the projected six movements of what he called Livre pour Quatuor were performed (and recorded); the work only reached its final form after the composer’s death and almost 70 years after it was conceived, when in 2017 the composer Philippe Manoury completed the reconstruction of the fourth and longest of its movements.

When planning the quartet, Boulez had taken Beethoven’s late quartets and Berg’s Lyric Suite as his starting points, not so much as models to follow but to react against. The language of Livre generates its energy from the tension between the ghosts of the classical forms and the pointillist total serialism that the postwar generation of composers had fashioned from the music of Webern and Messiaen. From the start, too, Boulez had envisaged it as a modular work, from which performers could select which movements to play, and in what order, with a title echoing the symbolist poet Mallarmé’s Livre, a book whose loose-leaf pages could be read in any order.

Quatuor Diotima were able to work on the score of Livre with Boulez in the last decade of his life, clarifying his intentions and unravelling the technical challenges. They recorded the five-movement version nine years ago, but this new disc, including the first ever recording of the fourth movement, is now the one to hear; the performance has tremendous confidence and authority and marvellously conveys the work’s vertiginous contrasts, between austere stillness and frantic activity, spare, etiolated textures against dense exuberance. If Livre pour Quatuor remains one of Boulez’s most challenging scores, this disc will gain it many new admirers.

Listen on Apple music (below)