At 70, Philip Glass is still full of surprises. And it’s no exaggeration to state that Book of Longing, his new 105-minute song cycle based on poetry and images from a recent book by Canadian singer-songwriter Leonard Cohen, includes some of the most surprising music he has ever composed.

Specifically, I’m thinking of five unaccompanied instrumental interludes — one apiece for cellist Wendy Sutter, violinist Tim Fain, oboist Kate St. John, saxophonist Andrew Sterman and double bassist Eleonore Oppenheim — in which Glass effectively dispensed altogether with the whirling arpeggios and nearly static harmonic progressions on which his style has been based for decades.

Graceful and ruminative, those solo passages seemed to exist in a space where time had been abolished. Sutter’s solo acknowledged Bach, while Fain’s alluded to the virtuoso cadenza. St. John’s section had a snaky, sensuous allure; Sterman’s was like overhearing a jazz musician blowing near an open window in a noir soundtrack. Oppenheim’s was the most dramatic, melodies playing up and down the entire range of her instrument.

If the rest of Book of Longing was more recognizably the work of Glass, it still stood apart from the bulk of his familiar oeuvre. His ensemble — the five performers already mentioned, Glass and Michael Riesman on keyboards, and Mick Rossi on keyboard and percussion — accompanied four vocalists: soprano Dominique Plaisant, mezzo Tara Hugo, tenor Will Erat and bass-baritone Daniel Keeling. The singers, all amplified, performed in a style traditionally associated with musical theater, or even cabaret. Among Glass’s works, it was probably closest in style to his 1986 cycle Songs from Liquid Days, but it was closer still in sound to John Adams’s 1995 "song-play," I Was Looking at the Ceiling and Then I Saw the Sky.

The singers prowled the stage in front of the musicians in a loose choreography designed by director Susan Marshall; behind the players, designer Christine Jones’s backing wall held oversize reproductions of the art-brut sketches from Cohen’s book: unflattering self-portraits in styles that resembled Matisse, Picasso, Cocteau and Japanese calligraphy, roughly rendered female backsides, and other small odds and ends. ("Windows into Leonard Cohen’s life," my perceptive TONY colleague Gabriella Gershenson suggested.)

Taken on its own, Glass’s music was subtle and expressive, and included some of the most beguiling timbral combinations I’ve ever heard in his work. His text setting was clear and efficient. But what the music lacked was an earthiness that is somewhere near the very core of what makes Cohen’s art so effective. Glass’s settings worked best when Cohen was in a droll state of mind, as in "This Morning I Woke Up Again," which includes the following memorable passage:

It’s fun to run in Heaven
When you’re off the beaten track
The Lord is such a monkey
When you’ve got him on your back

Here, Glass’s repetitive structures underscored the absurdity of Cohen’s verse. But when Glass took on Cohen’s "The Night of Santiago," a vivid poem inspired by Lorca, the composer’s idiom was incapable of conveying the erotic undercurrents of Cohen’s words. You got the sense that while Cohen might be sweating rather a lot, Glass remained cool and dry.

The singers all did well with their assignments; Hugo and Keeling were especially effective in a full-blown cabaret sort of way, and Glass’s ensemble writing was frequently outstanding. The voice truest to Cohen’s idiom was, unsurprisingly, his own: heard in a handful of grave, smoky recorded interludes presented without accompaniment. The musicians performed magnificently; I remember wondering at one point whether such romantic effulgence would even have been imaginable during the long-ago loft days of the early Philip Glass Ensemble.

Ultimately, Book of Longing works best when viewed as one artist’s affectionate portrait of another, rather than as an actual collaboration. All the facets of Cohen’s character were represented: the world-weary stance, the mordant wit, the irreverant view of the sacred, the abundant libido. Glass clearly crafted this portrait with genuine engagement and respect. But in the end, little empathy for Cohen’s darker passions came through.

Allan Kozinn took a more positive view in his New York Times review of Saturday night’s performance, posted just a few moments ago. As it turned out, my thoughts were more in line with what Greg Quill wrote about the world premiere in the Toronto Star, although I sense that I probably liked it more than he did. For supplemental reading, have a look at this fine Cohen interview that appeared in the London Times on July 1; I’d love to tell you who wrote it, but I can’t figure it out from the paper’s awful web layout.

Playlist:

Philip Glass – Music in 12 Parts, Parts 1-6 (Orange Mountain Music downloads); Music with Changing Parts (Nonesuch); and Koyaaniqatsi (Nonesuch)