The Book of Hours, by New York-based composer/saxophonist Patrick Zimmerli supported by the Belgian little big band Octurn with previous collaborator Ben Monder guesting on guitar, should appeal to a broad spectrum of jazz listeners from straight-ahead to avant-garde. For those of the more straight-ahead persuasion, the album presents music of great beauty and melodicism; Zimmerli employs often bright and crisp colors and textures (fully realized here by the ten likeminded musicians of Octurn), and there is also a warmth that suggests the post-Gil Evans approaches of a composer like Maria Schneider. In short, The Book of Hours is engaging and accessible throughout, and shouldn't scare potential straight-ahead jazz listeners away, at least those not bound by rigid stylistic constraints. And listeners with a non-traditional streak should find favor in the polyphonic complexity of Zimmerli's scores, which disguise and embellish head-solos-head structures in unconventional ways (the canon-like "Interlude" segments have a particularly strong classical influence, beginning in duet form and adding instruments cumulatively during trio, quartet, and sextet iterations interspersed among the other album tracks). Thematic material (signifying the many moods of a passing day) is stated and restated in variation as soloists enter and exit against an always surprising and involving backdrop — this is music that could keep even the most dedicated avant-gardist on his or her toes with its constantly evolving permutations. However, if you are an avant-garde jazz fan who favors apocalyptic free jazz filled with outbursts of dissonance, overblown multiphonics, and ear-splitting squeals, The Book of Hours is emphatically not for you. Zimmerli's music can be bold, energetic, and propulsive ("Night"), yet it often maintains a subtle and understated quality; even the seemingly highly improvised dialogue between baritone saxophone and percussion on "Noon" suggests a conversation rather than a shouting match. As for Zimmerli the saxophonist, his soprano solo on the lovely "Sleep" that concludes the disc is a thing of true beauty and one of the album's most striking improvisational moments, even as the piece tends to calm rather than excite the listener's heart.