Visitors to New York County Defender Services, part of the network of public defender offices that represent people charged with crimes in New York City who can’t afford to hire lawyers, will be forgiven for thinking they’ve arrived at the wrong address. Instead of a warren of cramped offices in the bowels of some decrepit courthouse, NYCDS occupies the 20th floor of a sleek office tower in the Financial District. The vibe is more Succession than Law & Order: frosted-glass conference rooms, corner offices with commanding views, the quiet hum of business being competently attended to.

After a discreet signal from an assistant, the firm’s legal director, Sergio de la Pava, steps out of his office and says hello. Dressed in a gray suit and starched white shirt, no tie, he looks a little like a lawyerly Diego Maradona—compact, purposeful, his jet-black curls flecked with a spot or two of gray. There’s an intensity about him that one might expect from a career public defender or a writer of sprawling, unapologetic postmodernist fiction. De la Pava happens to be both.

This fall, he’ll publish his fourth novel, a mind-bending detective story set in Cali, Colombia. But first, the backstory: 16 years ago, de la Pava caused an unlikely lit-world stir when he self-published his 678-page debut, A Naked Singularity, after it was turned down by 88 agents. His wife, Susanna, took on the role of publicist, pitching the maximalist tale of a young public defender who plots to commit the perfect crime to critics who had written about Infinite Jest. A couple of raves in online literary journals brought it to the attention of the University of Chicago Press, which reissued it in 2012; it went on to win the PEN/Robert W. Bingham Prize for debut fiction.

“I was a lot more petty than I am now,” de la Pava tells me, after we’ve taken a seat at a small conference table in a corner office. He explains that when it came time to discuss Chicago’s plans for A Naked Singularity, he insisted it be reissued “word for word,” typos included. “I figured once Chicago published it, there would be a better response. And I didn’t want [the agents who passed on it] to have the crutch of, ‘Well, this isn’t what I looked at—an adult came into the room and fixed it.’ They love these preexisting narratives, and I just wasn’t going to give them that.”

Pettiness aside, it’s fair to say de la Pava still has a chip from those days firmly lodged in his shoulder. Eighty-eight rejection letters will do that, especially when the agents who sent them weren’t saying, “Don’t quit your day job, this isn’t for you.”

“It was much more disheartening than that,” he explains. “It was, ‘Wow. This is brilliant. You’re amazing. Please don’t ever write me again.’ In many ways, that was the most dispiriting answer you could get, because it wasn’t, ‘You’re deluding yourself. The quality is not here.’ It was, ‘You’re right about quality, but who cares?’ ”

Not until Chicago said they were going to republish A Naked Singularity did de la Pava feel “the freedom to really dive into” his second novel, Personae, a slimmer if equally ambitious amalgam of murder mystery, existentialist drama, and absurdist comedy. He self-published that one, too, before Chicago reissued it in 2013. Then came the jump to the Big Five with 2018’s Lost Empress (Pantheon), which weaves together the stories of an NFL owner’s vengeful daughter, a parking garage attendant’s sensitive young son, and a criminal mastermind imprisoned on Rikers Island. Up next is Every Arc Bends Its Radian (Simon & Schuster, Nov.), which reads a bit like if Raymond Chandler and Jules Verne dropped acid together and started contemplating the nature of evil and the future of artificial intelligence.

Summarizing any de la Pava novel—where formal hijinks abound and digressions range from The Honeymooners to theoretical physics—in one sentence feels almost obscenely reductive, but even those bare-bones descriptions make clear that this is not a writer in search of approval. Or, as de la Pava puts it, “I’m not going to try to adapt what I do to the demands of the market, something hideous like that.” He credits the “unmitigated, perfect freedom” he had in writing and publishing A Naked Singularity for instilling in him the wherewithal to “refuse to let that go.” Each of his subsequent novels has been simply “an attempt by me to execute a vision I had.”

Of course, having a day job with such high stakes helps to keep one’s writerly ambitions pure. For de la Pava, the son of Colombian immigrants who grew up in Union City, N.J., and became a public defender straight out of Brooklyn Law School, writing is both a “form of play” and “as serious as a heart attack.” He bristles at the notion of weighing one career against the other. “It’s almost like asking someone, ‘I noticed you go to church every weekend. Is your religion as important as your career as an accountant?’ I couldn’t find more satisfaction in the creation of these works than I do now. It just clicks every button.”

The writer bug bit de la Pava when he was eight years old and spending the summer in Colombia. Desperate to read something in English, he grabbed a copy of The Old Man and the Sea from his grandmother’s shelf and tore through it. On the back cover was a picture of Ernest Hemingway; it was the first time de la Pava understood what an author is. “This guy is the reason this thing exists,” he recalls thinking. And then: “I want to be the reason something like this exists.”

Though he began writing stories at an early age, by the time de la Pava entered college at Rutgers University in the late 1980s, he’d developed the strong “public interest bent” that propelled him through law school and into a career in indigent defense. “There’s an electricity to representing someone who is in deep trouble, or even minor trouble,” he says. “And that can become addictive pretty quickly.”

The flip side, of course, is that fighting systemic injustice on a daily basis might leave one feeling not just electrified but burnt-out and hopeless. Riv del Rio, the protagonist of Every Arc Bends Its Radian, returns from New York to Colombia (where he, too, spent a fateful summer when he was eight) following a devastating personal loss. Despite his plans to lay low, barely 48 hours after his arrival in Cali he agrees to track down a missing cousin, who it soon becomes clear is in the clutches of the city’s most ruthless crime boss, Exeter Mondragon. For Riv’s relatives, the mere mention of Mondragon’s name is reason enough to abandon the search. Riv, however, presses on, launching a surreal quest that eventually brings him into contact with a heart of darkness beating far below the surface of Colombia’s haunted terrain.

The compulsion to press on in the face of insurmountable odds is a trait shared by many of de la Pava’s characters. Asked how it relates to his work as a public defender, he draws a distinction between the “cosmic injustice” of something like pediatric cancer and the “human injustice” of mass incarceration, which “we can convince others of and remedy.” His own career has spanned from the bad old days of stop and frisk and mandatory minimums to the current era of progressive prosecutors and conviction integrity units. That sea change happened, he says, because people like him “put their nose to the grindstone and came to work and fought against this machine.”

As de la Pava sees it, truth is both the primary weapon in the battle against injustice and his main objective as a storyteller. “I want to give you truth,” he says, leaning across the table like a co-conspirator—or a trusted counselor. “I want you, meaning you the reader, and I to work together to achieve a kind of understanding.” Or, as he puts it when describing Riv’s insistence on finding out what happened to his cousin, no matter the cost to his own life: “That’s another way of saying I’m here to seek truth. And yes, everything around me is fucked up, but truth is still truth. It’s a thing we should all be seeking.”