That there is an easily identifiable Glass “sound” is one of the few pieces of contemporary-classical-music shorthand that has made it into the pop-culture lexicon. Photograph by Gregory Bull / AP

In his 1980 short story “Company,” Samuel Beckett begins one paragraph with the sentences: “Another trait its repetitiousness. Repeatedly with only minor variants the same bygone.” When he wrote those lines, did Beckett already know that the composer Philip Glass would eventually provide the music for a staged version of the piece, at New York’s Public Theater, three years later? It’s fun to imagine that the writer had in mind Glass’s aesthetic, in which “music with repetitive structures” undergoes constant, subtle change—perhaps with a riff that evolves by having a single note added to or subtracted from it each time around.

Glass doesn’t say so, though, in his new autobiography, “Words Without Music.” Still, what the composer does relay about his connection to Beckett helps one to better understand Glass’s ever-growing body of work—particularly his operas, of which there are currently twenty-six, according to the composer’s Web site (but check back again next week). When describing his initial post-Juilliard years, Glass recalls the sense of freedom that the ascendant modernists of the late nineteen-sixties had bequeathed to the younger generation: “We didn’t have to destroy the idea of the novel—Beckett’s Molloy and Malone Dies had done that. In many ways, [John] Cage and Beckett cleared the playing field and gave us permission to start playing again. We were the beneficiaries.” Nor was Glass’s Beckett connection limited to a general appreciation of the era’s experimental zeitgeist. Decades later, when he was writing music to go with “Company,” the composer received only a single line of instruction from Beckett, which would also have a lasting impact: “The music should go into the interstices of the text, as it were.”

That there is an easily identifiable Glass “sound” is one of the few pieces of contemporary-classical-music shorthand that has made it into the pop-culture lexicon. Each listener new to the Glass oeuvre takes note of the music’s repetition—or its “minimalism” (a much-debated term, which the composer himself dislikes). Writers for “The Simpsons” have used this sonic brand, along with Glass’s name recognition, as fodder for jokes in multiple decades_ _of the show’s run. And as the musicologist Richard Taruskin chronicled in the final volume of his “Oxford History of Western Music,” this popular attention has stoked the suspicions of some classical specialists, who seem to suspect that some sort of con is being perpetrated by a mass-producing fraud. (Never mind that great composers from other eras also produced reams of similar-sounding work.)

In fact, Glass’s operatic repertoire displays a diverse range of narrative and emotional effects constructed from this supposedly same-y aesthetic. There is the explosive, non-narrative experimentalism of “Einstein on the Beach”_ _(co-conceived with the avant-garde theatre director Robert Wilson); the sublime (and even tear-jerking) nobility of “Satyagraha,” Glass’s opera on Gandhi’s years in South Africa; the gently surreal and occasionally comic qualities of Glass’s trilogy of operas adapted from films by Jean Cocteau; and, more recently, the angsty Austrian absurdism of “The Lost,” adapted from a play by the dramatist Peter Handke. Those six operas are merely my own favorites, based on the live performances and recordings I’ve heard. But I don’t think it’s purely a matter of personal taste: each of these music dramas features an abstract relationship between sound and text that mirrors Glass’s theatrical tastes, as related in “Words Without Music.”

Though Glass denies being “a literary person,” he seems proud of his wide-ranging taste in books—in one chapter, about a formative period studying in Paris, he gives us his opinions on the existentialists (“full of self pity”) and Jean Genet (“what I liked … was his exuberance and his complete disdain for all things conventional”), before coming to the matter of Beckett, whom Glass cites as a key inspiration behind the changes that would kick off his mature career as a composer. When creating the incidental music for a 1965 production of “Play_”_—a love-triangle one-act that Beckett’s stage notes nudge toward incomprehensibility (“Rapid tempo throughout. … Voices faint, largely unintelligible”)—Glass writes that Beckett’s text “provided no clue as to what the emotional shape of the music might be … I was thereby liberated from the necessity of shaping the music to fit the action, or even to not fit the action.”

Responding to this prompt, Glass scored Beckett’s rapid-fire writing for three actors with “a series of short, twenty- to thirty-second duets for two soprano saxophones. Each instrument had only two notes for each segment,” Glass explains, “and they were played in repetitive and unmatched rhythmic phrases. The effect was of an oscillating, constantly changing musical gesture. I composed about eight or ten of these and then recorded them.”

I was told by representatives for Glass’s label, Orange Mountain Music, that these recordings did not survive, alas. But, as Glass notes in “Words Without Music,” his first string quartet directly followed the epiphany he experienced while writing the music for “Play_”_; in the quartet, you can hear how Glass applied “the same technique of structure and discontinuity … but this time for four string parts. … Clearly this new music,” Glass writes, “was born from the world of theater.”

Or, rather, it was born from a particular idea of the theatre, rooted in the midcentury avant-garde. Glass shows, throughout the book, his awareness of the dramatic principles that separate Shakespeare from, say, Brecht—and it’s never a secret how the composer’s own tastes are ordered. Given a choice, Glass opts for the theatre of “distance,” one that harmonizes with John Cage’s conceptual dictum that audience members complete the performance of some music by dint of paying attention.

It’s a thought that Glass has carried into some of his more commercial projects. When writing about his career as a film composer, Glass observes that “in commercials and propaganda” no such distance between sound and image is allowed. Naturally, Glass prefers another approach. “When you listen to a piece of music and you look at an image at the same time, you are metaphorically making a journey to that image,” he writes. “And it’s in that journey that the spectator forms a relationship to the music and the image. Without that, it’s all made for us and we don’t have to invent anything.”

This seems like a fair yardstick to use when looking at Glass’s own operas. Part of what makes “Einstein on the Beach_”_ feel like such an event, upon each revival, is the mystery of the relationship between its stage images, its abstract texts, and Glass’s music. But when I listen to latter-day Glass operas on the subject of science, such as “Kepler_”__ _and “Galileo Galilei,” it seems as though there’s more spoon-feeding going on in his orchestra pit: when the scientist is under threat, the score deals out ominous, stomping progressions; when creative discovery is the point of a scene, more gracefully flowing arpeggios emerge. Glass’s respect for scientists seems to clasp these operas so closely to the composer’s chest that little of his desired theatrical distance remains.

It seems no accident that, in his best pieces, Glass’s intellectual affinities find more original modes of theatrical expression. You can’t come away from “Satyagraha_”__ _without an understanding of Glass’s reverence for Gandhi. But his choice to use the Bhagavad Gita, in the original Sanskrit, as the libretto keeps the audience “inventing.” (The Hindu text has thematic resonance to the story, of course, but its relationship to the stage action also allows for moment-to-moment ambiguity.)

Likewise, Glass’s decision to sync his operatic adaptation of the Jean Cocteau film “La Belle et la Bête_”_ to the precise timing of the movie creates a humorously weird doubling effect that respects and responds to the director’s ingenious optical illusions. (You can experience this for yourself in the Criterion Collection’s Blu-ray edition of the Cocteau milestone, which includes Glass’s opera as a soundtrack option.) At several points in “Words Without Music,” Glass ably describes his musical strategies for inserting dramatic jolts into his purely instrumental works. But it’s the single piece of advice that Glass received from Beckett, about inserting his music “into the interstices of the text,” that sounds like a still-useful instructional mantra for the many Glass operas that are, hopefully, yet to come.