NEW YORK, NY.- Frank London is one of those musicians who somehow seems to be everywhere, participating in a bit of everything. At 66, the trumpeter, composer, arranger and bandleader has collaborated with everyone from Mel Tormé to LL Cool J. A founding member of the Klezmatics, a band that helped to revitalize the klezmer style during the late ’80s, London has worked for decades at a fertile crossroads where Jewish music meets downtown jazz. With two new albums involving both styles arriving imminently, he arranged to throw a party, and invited dozens of friends and colleagues to play.

The celebration in New York City, happening Monday at the Brooklyn venue Roulette, features the Klezmatics alongside three of London’s bands: Conspiracy Brass, a buoyant, funky horns-and-percussion aggregation; the Elders, a soulful, hard-swinging quintet of seasoned jazzers; and Klezmer Brass Allstars, who meld traditional Yiddish and Hasidic music with electronic beats.

The only thing missing will be London himself, now hospitalized for treatment of a rare cancer he became aware of four years ago. During unrelated medical testing in 2020, doctors detected signs of myelofibrosis, a chronic leukemia characterized by a buildup of scar tissue in the bone marrow. The median survival rate for the disease is six years.

“I didn’t tell anyone much about it, because this is a very weird disease,” London said during an interview before his hospitalization, in the cozy East Village apartment he shares with his wife, Tine Kindermann, an artist and musician.

“Some people die within a year,” he said. “Some people live with it for 30 years. I’m in this statistical norm where it’s like, after three to five years it starts to get worse. So for the last four years, I’ve just been leading my life.”

For London, that meant taking care of business. In addition to wrapping up his two new albums, “Brass Conspiracy” by Conspiracy Brass and “Spirit Stronger Than Blood” by the Elders, he delivered a Klezmer Brass Allstars album, “Chronika,” in December. He wrote music for an independent film, completed a score for a forthcoming Karin Coonrod production of “King Lear,” and recorded a commissioned set of niggunim — Jewish spiritual melodies — with a starry ensemble of fellow iconoclasts.

Two months ago, doctors told London that his cancer had rapidly grown more serious. Treatment would involve a huge dose of chemotherapy to destroy his diseased bone marrow, followed by a stem cell transplant. Assuming success, it would be months before he would know if he would be able to resume his musical career.

“I don’t even go there,” London said. “I’m thinking about now, thinking about finishing these projects.” He dedicated his celebratory concert to fellow artists who died of myelofibrosis and related cancers, including cornetist Ron Miles, singers Adrienne Cooper and Jewlia Eisenberg, and writer Isabelle Deconinck, and to a myelofibrosis survivor he discovered via the internet: Mike Derks, who performs as BälSäc the Jaws ‘o Death in the costumed heavy-metal band Gwar.

“And I don’t think much past that,” he said, “because I’m not going to waste a day where I feel good.”

Even so, a rash of recent activities conspicuously included reunions with formative associates. After the interview at his home, London raced to Brooklyn’s Park Slope neighborhood to play with improvising conductor Walter Thompson. The day before, he’d been in Houston, performing with Itzhak Perlman in a revival of the violinist’s celebrated Jewish-music odyssey, “In the Fiddler’s House.” That engagement reunited London not only with Perlman, but with the Klezmer Conservatory Band, whose founder, Hankus Netsky, had initiated him decades earlier into a then-unknown world of Jewish music.

In a video interview, Netsky — now the co-chair of New England Conservatory’s Contemporary Musical Arts Department — recalled the determined 12-year-old trumpeter from Long Island he’d met while working as a teenage counselor at Lighthouse Art and Music Camp in Pine Grove, Pennsylvania.

“I always tell my students that if you want to be a creative musician, you’ve got to have technique on your instrument, you’ve got to channel your life experience, whatever that is, you have to know a certain amount of repertoire, and you have to have creativity,” Netsky said. “He had all of them, obviously. But the creativity was off the charts.”

Raised in what he called a religious Reform Jewish household in Plainview, New York, London gravitated toward rock music in high school. But at the school’s radio station, he discovered recordings on Strata-East, a Brooklyn label run by jazz musicians Charles Tolliver and Stanley Cowell, and was taken with one of its more adventurous releases: “Sound Awareness,” a choir-enhanced, percussion-heavy forebear of what’s now called spiritual jazz, by an artist called Brother Ah.

Enrolling in Brown University, London discovered that Brother Ah, born Robert Northern, was teaching improvisation there. When he decided to pursue improvised music as a career, London left Brown and auditioned for the New England Conservatory, where Netsky was teaching. He failed the audition, but paid to take classes anyway, and played in a workshop band Netsky led with pianist Jaki Byard.

There, he absorbed the work of canonical jazz trumpeters like Dizzy Gillespie and Miles Davis, along with innovators such as Olu Dara and Lester Bowie, Netsky recalled. But he was never a purist. “He was listening to Hugh Masekela, he was listening to reggae, he was listening to ska,” Netsky said. “The world was completely open to this guy.”

Seeking further new sounds, London and his classmates went crate-digging in local record stores, focusing on the world-music bins. “We had big listening parties, and started transcribing a lot of brass-band stuff,” composer and woodwind player Matt Darriau wrote in an email. “We were especially interested in the music we would get on hard-to-find LPs and obscure cassettes brought by musicians traveling from the Balkans.”

That interest led to the formation of Les Misérables Brass Band, which would evolve from a student-recital project to touring with David Byrne and performing at the Public Theater with Lester Bowie. “People playing Bulgarian brass music all over the United States, playing all kinds of brass music from different cultures everywhere,” free-spirited trumpeter Steven Bernstein said, “if Frank wasn’t the first, I don’t know who was.” Bernstein, who jokes about routinely being mistaken for London, dashed to his record shelves during a video interview to retrieve rare LPs he’d learned about from London.

London was also playing free jazz with another group, Ensemble Garuda, when Netsky tapped him to join a workshop band digging into the then-obscure klezmer music he’d found in his great-grandfather’s vintage record collection — a project that became the Klezmer Conservatory Band.

On moving to New York, London responded to an ad seeking klezmer players, and met the musicians with whom he formed the Klezmatics, the most adventurous and successful band of the klezmer revival. Steeped in Hasidic music through countless wedding gigs, London and saxophonist Greg Wall formed Hasidic New Wave to infuse traditional melodies with punk-rock spirit. Recording for John Zorn’s Tzadik label, London explored Jewish liturgical music with renowned cantor Jacob Mendelson.

For tuba player Marcus Rojas, a longtime friend who now plays in Conspiracy Brass, his bandmate’s omnivorousness has been instructive. “These notions of how to keep the juicy and meaningful parts of different musics, while creating something new, touched everything he did,” Rojas wrote in an email. “That idea is a very New York thing in general, but he and all of the musicians we liked playing with took it to a completely other level.”

However closely London has been associated with Jewish music, his faith hasn’t had a large role in his approach to his malady. “My Jewish friends are asking me for my Jewish name, so that they can say a certain healing prayer for me, and I appreciate that,” he said.

He’s been preparing for the ordeal ahead by reading Stoic philosophy concerning the inevitability of death.

“Seneca says that people who don’t look at that in their life, when something goes really bad, they’re affected much worse because they’re not prepared for it,” he said. “But if you’re someone like me, who’s always been aware that everything wonderful in my life is a gift to be appreciated and could be over at any second, you’re more prepared when something really devastating comes along. So in many ways, a concert like this is a chance to express gratitude.”

This article originally appeared in The New York Times.