It’s been more than 20 years since Nonesuch Records released“The John Adams Earbox,”a 10-disc retrospective of the work of the Berkeley composer. At the time, the collection felt authoritative, a definitive accounting of one of the most important achievements in American classical music of the late 20th century.

It turns out that was just the beginning.

As the musical world waits eagerly for Adams’ next big reveal — the Sept. 10 premiere of his new opera, “Antony and Cleopatra,” commissioned to celebrate thecentennial of the San Francisco Opera— Nonesuch has released an even more expansive walk-through for the remarkable arc of this composer’s career. “John Adams: Collected Works,” a massive 40-disc box set, includes just about everything of note, from the proto-minimalist forays of the 1970s and early ’80s up through the thunderous explosions of Adams’ magnificent2018 piano concerto“Must the Devil Have All the Good Tunes?”

Taken together, the set does everything an overview of one creative career should do. It illuminates both the stylistic premises and the specific artistic choices Adams has adopted over nearly a half-century of dedicated creative effort. It traces a compelling chronological narrative, as Adams uncovers a distinctive musical voice and then pursues it in a myriad of diverse but fundamentally related directions.

But most elementally, the set provides enormous amounts of damn fine listening. This is hours’ worth of music that is exciting, beautiful, inventive, funny and heart-stoppingly original — sometimes in succession, sometimes all at once. It will leave you with melodies and entire musical episodes bouncing ingratiatingly around in your head for days.

To a certain extent, all this was already in place in 1999’s “Earbox,” which documented Adams’ career up to the turn of the millennium. Many of those early recordings are back again to serve as a foundation of the new set, including the choral masterpiece “Harmonium,” the gloriously tender Walt Whitman setting“The Wound-Dresser”(expressively sung by the late baritone Sanford Sylvan), and the still-undervalued 1991 tone poem “El Dorado.”

But even some of those offerings have returned in expanded form. Adams’ first two operas, “Nixon in China” and “The Death of Klinghoffer,” as well as the hard-to-classify pop-tinged “songplay” titled “I Was Looking at the Ceiling and Then I Saw the Sky,” were both originally represented by excerpts. Now they’re presented in their entirety — not only with audio, but in the case of “Nixon” with a 2011 Blu-ray video presentation from the Metropolitan Opera.

除此之外的重要的部分s — both big and small, but mostly big — from Adams’ past two decades. The opera“Doctor Atomic”is here in full, along with the symphony derived from its thematic material. So is “On the Transmigration of Souls,” the 9/11 memorial for which Adams won the2003 Pulitzer Prize for music.

There are the not-exactly-operatic stage works, “El Niño,”“A Flowering Tree”and“The Gospel According to the Other Mary.”There are concertos for violin, piano, saxophone and string quartet, and the ongoing fruit of Adams’ trademark formal innovation, the three-movement orchestral tone poem (exemplified by, among others, the richly imagined “Naïve and Sentimental Music”).

The set even includes recordings of Adams conducting the music of other composers, including Charles Ives, Morton Feldman and the late Ingram Marshall.

Not included, for better or worse, is Adams’ previous opera,“Girls of the Golden West,”which struckat least one listeneras an artistic misfire of epic proportions. Perhaps the context of the composer’s entire catalog would have put a different spin on the score.

In any case, the set bristles with discoveries and rediscoveries, old truths confirmed and new ones unveiled.

One key takeaway — not a new insight, but one that keeps taking on added dimensions — is how central the orchestra is to Adams’ imagination, and how deftly he deploys it. Nearly everything he’s written comes through in a vibrant web of instrumental color, using the traditional orchestral lineup and supplementing it with inventive ringers such as the cimbalom, a hammered dulcimer.

A related aspect is how consistently Adams operates on the broadest of formal canvases. The catalog of nearly every other major composer, past or present, is studded with little one-off endeavors — a chamber piece, a piano sonata, a fanfare written for a special occasion. Adams has a few of these in the lineup, but they don’t figure very prominently; he’s always more interested in taking the big home-run swing.

The big agenda he has in mind is frequently a stylistic one. It’s reductive but basically accurate to say that Adams found his mature compositional voice with the 1985 orchestral work“Harmonielehre,”which forged a personal and thoroughly original fusion between the minimalism of Philip Glass and Steve Reich and the late-Romantic language of Sibelius and Wagner.

“Harmonielehre” still stands as the purest embodiment of that stylistic hybrid, and the single work that best sums up Adams’ legacy. It’s no accident that the piece comes both first and last in this collection, which leads with the original 1985 recording by Edo de Waart and the San Francisco Symphony, and concludes with a somewhat more vivid 2016 account by Adams and the Berlin Philharmonic.

But Adams’ language becomes omnivorous in other directions as well, including jazz. For me, the sharpest revelation here was the combination of “City Noir” — a buoyant big-band pastiche that had never quite made sense before — and the Saxophone Concerto, with tireless solo work by Timothy McAllister. It’s remarkable, too, to hear Adams develop an idiosyncratically maximalist approach to the concerto over the course of decades.

And more, and more, and more. There are hours of delight and admiration to be had here — perhaps just enough to tide us over until the arrival of “Antony and Cleopatra.”

John Adams: Collected Works:Nonesuch (40 discs). $172.