Last June, as dusk fell outside Tony Schwartz’s sprawling house, on a leafy back road in Riverdale, New York, he pulled out his laptop and caught up with the day’s big news: Donald J. Trump had declared his candidacy for President. As Schwartz watched a video of the speech, he began to feel personally implicated.

Trump, facing a crowd that had gathered in the lobby of Trump Tower, on Fifth Avenue, laid out his qualifications, saying, “We need a leader that wrote ‘The Art of the Deal.’ ” If that was so, Schwartz thought, then he, not Trump, should be running. Schwartz dashed off a tweet: “Many thanks Donald Trump for suggesting I run for President, based on the fact that I wrote ‘The Art of the Deal.’ ”

Schwartz had ghostwritten Trump’s 1987 breakthrough memoir, earning a joint byline on the cover, half of the book’s five-hundred-thousand-dollar advance, and half of the royalties. The book was a phenomenal success, spending forty-eight weeks on the Times best-seller list, thirteen of them at No. 1. More than a million copies have been bought, generating several million dollars in royalties. The book expanded Trump’s renown far beyond New York City, making him an emblem of the successful tycoon. Edward Kosner, the former editor and publisher of New York, where Schwartz worked as a writer at the time, says, “Tony created Trump. He’s Dr. Frankenstein.”

Starting in late 1985, Schwartz spent eighteen months with Trump—camping out in his office, joining him on his helicopter, tagging along at meetings, and spending weekends with him at his Manhattan apartment and his Florida estate. During that period, Schwartz felt, he had got to know him better than almost anyone else outside the Trump family. Until Schwartz posted the tweet, though, he had not spoken publicly about Trump for decades. It had never been his ambition to be a ghostwriter, and he had been glad to move on. But, as he watched a replay of the new candidate holding forth for forty-five minutes, he noticed something strange: over the decades, Trump appeared to have convinced himself that he had written the book. Schwartz recalls thinking, “If he could lie about that on Day One—when it was so easily refuted—he is likely to lie about anything.”

It seemed improbable that Trump’s campaign would succeed, so Schwartz told himself that he needn’t worry much. But, as Trump denounced Mexican immigrants as “rapists,” near the end of the speech, Schwartz felt anxious. He had spent hundreds of hours observing Trump firsthand, and felt that he had an unusually deep understanding of what he regarded as Trump’s beguiling strengths and disqualifying weaknesses. Many Americans, however, saw Trump as a charmingly brash entrepreneur with an unfailing knack for business—a mythical image that Schwartz had helped create. “It pays to trust your instincts,” Trump says in the book, adding that he was set to make hundreds of millions of dollars after buying a hotel that he hadn’t even walked through.

In the subsequent months, as Trump defied predictions by establishing himself as the front-runner for the Republican nomination, Schwartz’s desire to set the record straight grew. He had long since left journalism to launch the Energy Project, a consulting firm that promises to improve employees’ productivity by helping them boost their “physical, emotional, mental, and spiritual” morale. It was a successful company, with clients such as Facebook, and Schwartz’s colleagues urged him to avoid the political fray. But the prospect of President Trump terrified him. It wasn’t because of Trump’s ideology—Schwartz doubted that he had one. The problem was Trump’s personality, which he considered pathologically impulsive and self-centered.

Schwartz thought about publishing an article describing his reservations about Trump, but he hesitated, knowing that, since he’d cashed in on the flattering “Art of the Deal,” his credibility and his motives would be seen as suspect. Yet watching the campaign was excruciating. Schwartz decided that if he kept mum and Trump was elected he’d never forgive himself. In June, he agreed to break his silence and give his first candid interview about the Trump he got to know while acting as his Boswell.

“I put lipstick on a pig,” he said. “I feel a deep sense of remorse that I contributed to presenting Trump in a way that brought him wider attention and made him more appealing than he is.” He went on, “I genuinely believe that if Trump wins and gets the nuclear codes there is an excellent possibility it will lead to the end of civilization.”

If he were writing “The Art of the Deal” today, Schwartz said, it would be a very different book with a very different title. Asked what he would call it, he answered, “The Sociopath.”

The idea of Trump writing an autobiography didn’t originate with either Trump or Schwartz. It began with Si Newhouse, the media magnate whose company, Advance Publications, owned Random House at the time, and continues to own Condé Nast, the parent company of this magazine. “It was very definitely, and almost uniquely, Si Newhouse’s idea,” Peter Osnos, who edited the book, recalls. GQ, which Condé Nast also owns, had published a cover story on Trump, and Newhouse noticed that newsstand sales had been unusually strong.

Newhouse called Trump about the project, then visited him to discuss it. Random House continued the pursuit with a series of meetings. At one point, Howard Kaminsky, who ran Random House then, wrapped a thick Russian novel in a dummy cover that featured a photograph of Trump looking like a conquering hero; at the top was Trump’s name, in large gold block lettering. Kaminsky recalls that Trump was pleased by the mockup, but had one suggestion: “Please make my name much bigger.” After securing the half-million-dollar advance, Trump signed a contract.

Around this time, Schwartz, who was one of the leading young magazine writers of the day, stopped by Trump’s office, in Trump Tower. Schwartz had written about Trump before. In 1985, he’d published a piece in New York called “A Different Kind of Donald Trump Story,” which portrayed him not as a brilliant mogul but as a ham-fisted thug who had unsuccessfully tried to evict rent-controlled and rent-stabilized tenants from a building that he had bought on Central Park South. Trump’s efforts—which included a plan to house homeless people in the building in order to harass the tenants—became what Schwartz described as a “fugue of failure, a farce of fumbling and bumbling.” An accompanying cover portrait depicted Trump as unshaven, unpleasant-looking, and shiny with sweat. Yet, to Schwartz’s amazement, Trump loved the article. He hung the cover on a wall of his office, and sent a fan note to Schwartz, on his gold-embossed personal stationery. “Everybody seems to have read it,” Trump enthused in the note, which Schwartz has kept.

“I was shocked,” Schwartz told me. “Trump didn’t fit any model of human being I’d ever met. He was obsessed with publicity, and he didn’t care what you wrote.” He went on, “Trump only takes two positions. Either you’re a scummy loser, liar, whatever, or you’re the greatest. I became the greatest. He wanted to be seen as a tough guy, and he loved being on the cover.” Schwartz wrote him back, saying, “Of all the people I’ve written about over the years, you are certainly the best sport.”

And so Schwartz had returned for more, this time to conduct an interview for Playboy. But to his frustration Trump kept making cryptic, monosyllabic statements. “He mysteriously wouldn’t answer my questions,” Schwartz said. After twenty minutes, he said, Trump explained that he didn’t want to reveal anything new about himself—he had just signed a lucrative book deal and needed to save his best material.

“What kind of book?” Schwartz said.

“My autobiography,” Trump replied.

“You’re only thirty-eight—you don’t have one yet!” Schwartz joked.

“Yeah, I know,” Trump said.

“If I were you,” Schwartz recalls telling him, “I’d write a book called ‘The Art of the Deal.’ That’s something people would be interested in.”

“You’re right,” Trump agreed. “Do you want to write it?”

Schwartz thought it over for several weeks. He knew that he would be making a Faustian bargain. A lifelong liberal, he was hardly an admirer of Trump’s ruthless and single-minded pursuit of profit. “It was one of a number of times in my life when I was divided between the Devil and the higher side,” he told me. He had grown up in a bourgeois, intellectual family in Manhattan, and had attended élite private schools, but he was not as wealthy as some of his classmates—and, unlike many of them, he had no trust fund. “I grew up privileged,” he said. “But my parents made it clear: ‘You’re on your own.’ ” Around the time Trump made his offer, Schwartz’s wife, Deborah Pines, became pregnant with their second daughter, and he worried that the family wouldn’t fit into their Manhattan apartment, whose mortgage was already too high. “I was overly worried about money,” Schwartz said. “I thought money would keep me safe and secure—or that was my rationalization.” At the same time, he knew that if he took Trump’s money and adopted Trump’s voice his journalism career would be badly damaged. His heroes were such literary nonfiction writers as Tom Wolfe, John McPhee, and David Halberstam. Being a ghostwriter was hackwork. In the end, though, Schwartz had his price. He told Trump that if he would give him half the advance and half the book’s royalties he’d take the job.

Such terms are unusually generous for a ghostwriter. Trump, despite having a reputation as a tough negotiator, agreed on the spot. “It was a huge windfall,” Schwartz recalls. “But I knew I was selling out. Literally, the term was invented to describe what I did.” Soon Spy was calling him “former journalist Tony Schwartz.”

Schwartz thought that “The Art of the Deal” would be an easy project. The book’s structure would be simple: he’d chronicle half a dozen or so of Trump’s biggest real-estate deals, dispense some bromides about how to succeed in business, and fill in Trump’s life story. For research, he planned to interview Trump on a series of Saturday mornings. The first session didn’t go as planned, however. After Trump gave him a tour of his marble-and-gilt apartment atop Trump Tower—which, to Schwartz, looked unlived-in, like the lobby of a hotel—they began to talk. But the discussion was soon hobbled by what Schwartz regards as one of Trump’s most essential characteristics: “He has no attention span.”

In those days, Schwartz recalls, Trump was generally affable with reporters, offering short, amusingly immodest quotes on demand. Trump had been forthcoming with him during the New York interview, but it hadn’t required much time or deep reflection. For the book, though, Trump needed to provide him with sustained, thoughtful recollections. He asked Trump to describe his childhood in detail. After sitting for only a few minutes in his suit and tie, Trump became impatient and irritable. He looked fidgety, Schwartz recalls, “like a kindergartner who can’t sit still in a classroom.” Even when Schwartz pressed him, Trump seemed to remember almost nothing of his youth, and made it clear that he was bored. Far more quickly than Schwartz had expected, Trump ended the meeting.

Week after week, the pattern repeated itself. Schwartz tried to limit the sessions to smaller increments of time, but Trump’s contributions remained oddly truncated and superficial.

“Trump has been written about a thousand ways from Sunday, but this fundamental aspect of who he is doesn’t seem to be fully understood,” Schwartz told me. “It’s implicit in a lot of what people write, but it’s never explicit—or, at least, I haven’t seen it. And that is that it’s impossible to keep him focussed on any topic, other than his own self-aggrandizement, for more than a few minutes, and even then . . . ” Schwartz trailed off, shaking his head in amazement. He regards Trump’s inability to concentrate as alarming in a Presidential candidate. “If he had to be briefed on a crisis in the Situation Room, it’s impossible to imagine him paying attention over a long period of time,” he said.

In a recent phone interview, Trump told me that, to the contrary, he has the skill that matters most in a crisis: the ability to forge compromises. The reason he touted “The Art of the Deal” in his announcement, he explained, was that he believes that recent Presidents have lacked his toughness and finesse: “Look at the trade deficit with China. Look at the Iran deal. I’ve made a fortune by making deals. I do that. I do that well. That’s what I do.”

But Schwartz believes that Trump’s short attention span has left him with “a stunning level of superficial knowledge and plain ignorance.” He said, “That’s why he so prefers TV as his first news source—information comes in easily digestible sound bites.” He added, “I seriously doubt that Trump has ever read a book straight through in his adult life.” During the eighteen months that he observed Trump, Schwartz said, he never saw a book on Trump’s desk, or elsewhere in his office, or in his apartment.

Other journalists have noticed Trump’s apparent lack of interest in reading. In May, Megyn Kelly, of Fox News, asked him to name his favorite book, other than the Bible or “The Art of the Deal.” Trump picked the 1929 novel “All Quiet on the Western Front.” Evidently suspecting that many years had elapsed since he’d read it, Kelly asked Trump to talk about the most recent book he’d read. “I read passages, I read areas, I’ll read chapters—I don’t have the time,” Trump said. As The New Republic noted recently, this attitude is not shared by most U.S. Presidents, including Barack Obama, a habitual consumer of current books, and George W. Bush, who reportedly engaged in a fiercely competitive book-reading contest with his political adviser Karl Rove.

Trump’s first wife, Ivana, famously claimed that Trump kept a copy of Adolf Hitler’s collected speeches, “My New Order,” in a cabinet beside his bed. In 1990, Trump’s friend Marty Davis, who was then an executive at Paramount, added credence to this story, telling Marie Brenner, of Vanity Fair, that he had given Trump the book. “I thought he would find it interesting,” Davis told her. When Brenner asked Trump about it, however, he mistakenly identified the volume as a different work by Hitler: “Mein Kampf.” Apparently, he had not so much as read the title. “If I had these speeches, and I am not saying that I do, I would never read them,” Trump told Brenner.

Growing desperate, Schwartz devised a strategy for trapping Trump into giving more material. He made plans to spend the weekend with Trump at Mar-a-Lago, his mansion in Palm Beach, where there would be fewer distractions. As they chatted in the garden, Ivana icily walked by, clearly annoyed that Schwartz was competing for her husband’s limited free time. Trump again grew impatient. Long before lunch on Saturday, Schwartz recalls, Trump “essentially threw a fit.” He stood up and announced that he couldn’t stand any more questions.

Schwartz went to his room, called his literary agent, Kathy Robbins, and told her that he couldn’t do the book. (Robbins confirms this.) As Schwartz headed back to New York, though, he came up with another plan. He would propose eavesdropping on Trump’s life by following him around on the job and, more important, by listening in on his office phone calls. That way, extracting extended reflections from Trump would not be required. When Schwartz presented the idea to Trump, he loved it. Almost every day from then on, Schwartz sat about eight feet away from him in the Trump Tower office, listening on an extension of Trump’s phone line. Schwartz says that none of the bankers, lawyers, brokers, and reporters who called Trump realized that they were being monitored. The calls usually didn’t last long, and Trump’s assistant facilitated the conversation-hopping. While he was talking with someone, she often came in with a Post-it note informing him of the next caller on hold.

“He was playing people,” Schwartz recalls. On the phone with business associates, Trump would flatter, bully, and occasionally get mad, but always in a calculated way. Before the discussion ended, Trump would “share the news of his latest success,” Schwartz says. Instead of saying goodbye at the end of a call, Trump customarily signed off with “You’re the greatest!” There was not a single call that Trump deemed too private for Schwartz to hear. “He loved the attention,” Schwartz recalls. “If he could have had three hundred thousand people listening in, he would have been even happier.”

This year, Schwartz has heard some argue that there must be a more thoughtful and nuanced version of Donald Trump that he is keeping in reserve for after the campaign. “There isn’t,” Schwartz insists. “There is no private Trump.” This is not a matter of hindsight. While working on “The Art of the Deal,” Schwartz kept a journal in which he expressed his amazement at Trump’s personality, writing that Trump seemed driven entirely by a need for public attention. “All he is is ‘stomp, stomp, stomp’—recognition from outside, bigger, more, a whole series of things that go nowhere in particular,” he observed, on October 21, 1986. But, as he noted in the journal a few days later, “the book will be far more successful if Trump is a sympathetic character—even weirdly sympathetic—than if he is just hateful or, worse yet, a one-dimensional blowhard.”

Eavesdropping solved the interview problem, but it presented a new one. After hearing Trump’s discussions about business on the phone, Schwartz asked him brief follow-up questions. He then tried to amplify the material he got from Trump by calling others involved in the deals. But their accounts often directly conflicted with Trump’s. “Lying is second nature to him,” Schwartz said. “More than anyone else I have ever met, Trump has the ability to convince himself that whatever he is saying at any given moment is true, or sort of true, or at least ought to be true.” Often, Schwartz said, the lies that Trump told him were about money—“how much he had paid for something, or what a building he owned was worth, or how much one of his casinos was earning when it was actually on its way to bankruptcy.” Trump bragged that he paid only eight million dollars for Mar-a-Lago, but omitted that he bought a nearby strip of beach for a record sum. After gossip columns reported, erroneously, that Prince Charles was considering buying several apartments in Trump Tower, Trump implied that he had no idea where the rumor had started. (“It certainly didn’t hurt us,” he says, in “The Art of the Deal.”) Wayne Barrett, a reporter for the Village Voice, later revealed that Trump himself had planted the story with journalists. Schwartz also suspected that Trump engaged in such media tricks, and asked him about a story making the rounds—that Trump often called up news outlets using a pseudonym. Trump didn’t deny it. As Schwartz recalls, he smirked and said, “You like that, do you?”

Schwartz says of Trump, “He lied strategically. He had a complete lack of conscience about it.” Since most people are “constrained by the truth,” Trump’s indifference to it “gave him a strange advantage.”

When challenged about the facts, Schwartz says, Trump would often double down, repeat himself, and grow belligerent. This quality was recently on display after Trump posted on Twitter a derogatory image of Hillary Clinton that contained a six-pointed star lifted from a white-supremacist Web site. Campaign staffers took the image down, but two days later Trump angrily defended it, insisting that there was no anti-Semitic implication. Whenever “the thin veneer of Trump’s vanity is challenged,” Schwartz says, he overreacts—not an ideal quality in a head of state.

When Schwartz began writing “The Art of the Deal,” he realized that he needed to put an acceptable face on Trump’s loose relationship with the truth. So he concocted an artful euphemism. Writing in Trump’s voice, he explained to the reader, “I play to people’s fantasies. . . . People want to believe that something is the biggest and the greatest and the most spectacular. I call it truthful hyperbole. It’s an innocent form of exaggeration—and it’s a very effective form of promotion.” Schwartz now disavows the passage. “Deceit,” he told me, is never “innocent.” He added, “ ‘Truthful hyperbole’ is a contradiction in terms. It’s a way of saying, ‘It’s a lie, but who cares?’ ” Trump, he said, loved the phrase.

In his journal, Schwartz describes the process of trying to make Trump’s voice palatable in the book. It was kind of “a trick,” he writes, to mimic Trump’s blunt, staccato, no-apologies delivery while making him seem almost boyishly appealing. One strategy was to make it appear that Trump was just having fun at the office. “I try not to take any of what’s happened too seriously,” Trump says in the book. “The real excitement is playing the game.”

In his journal, Schwartz wrote, “Trump stands for many of the things I abhor: his willingness to run over people, the gaudy, tacky, gigantic obsessions, the absolute lack of interest in anything beyond power and money.” Looking back at the text now, Schwartz says, “I created a character far more winning than Trump actually is.” The first line of the book is an example. “I don’t do it for the money,” Trump declares. “I’ve got enough, much more than I’ll ever need. I do it to do it. Deals are my art form. Other people paint beautifully on canvas or write wonderful poetry. I like making deals, preferably big deals. That’s how I get my kicks.” Schwartz now laughs at this depiction of Trump as a devoted artisan. “Of course he’s in it for the money,” he said. “One of the most deep and basic needs he has is to prove that ‘I’m richer than you.’ ” As for the idea that making deals is a form of poetry, Schwartz says, “He was incapable of saying something like that—it wouldn’t even be in his vocabulary.” He saw Trump as driven not by a pure love of dealmaking but by an insatiable hunger for “money, praise, and celebrity.” Often, after spending the day with Trump, and watching him pile one hugely expensive project atop the next, like a circus performer spinning plates, Schwartz would go home and tell his wife, “He’s a living black hole!”

Schwartz reminded himself that he was being paid to tell Trump’s story, not his own, but the more he worked on the project the more disturbing he found it. In his journal, he describes the hours he spent with Trump as “draining” and “deadening.” Schwartz told me that Trump’s need for attention is “completely compulsive,” and that his bid for the Presidency is part of a continuum. “He’s managed to keep increasing the dose for forty years,” Schwartz said. After he’d spent decades as a tabloid titan, “the only thing left was running for President. If he could run for emperor of the world, he would.”

Rhetorically, Schwartz’s aim in “The Art of the Deal” was to present Trump as the hero of every chapter, but, after looking into some of his supposedly brilliant deals, Schwartz concluded that there were cases in which there was no way to make Trump look good. So he sidestepped unflattering incidents and details. “I didn’t consider it my job to investigate,” he says.

Schwartz also tried to avoid the strong whiff of cronyism that hovered over some deals. In his 1986 journal, he describes what a challenge it was to “put his best foot forward” in writing about one of Trump’s first triumphs: his development, starting in 1975, of the Grand Hyatt Hotel, on the site of the former Commodore Hotel, next to Grand Central Terminal. In order to afford the hotel, Trump required an extremely large tax abatement. Richard Ravitch, who was then in charge of the agency that had the authority to grant such tax breaks to developers, recalls that he declined to grant the abatement, and Trump got “so unpleasant I had to tell him to get out.” Trump got it anyway, largely because key city officials had received years of donations from his father, Fred Trump, who was a major real-estate developer in Queens. Wayne Barrett, whose reporting for the Voice informed his definitive 1991 book, “Trump: The Deals and the Downfall,” says, “It was all Fred’s political connections that created the abatement.” In addition, Trump snookered rivals into believing that he had an exclusive option from the city on the project, when he didn’t. Trump also deceived his partner in the deal, Jay Pritzker, the head of the Hyatt Hotel chain. Pritzker had rejected an unfavorable term proposed by Trump, but at the closing Trump forced it through, knowing that Pritzker was on a mountain in Nepal and could not be reached. Schwartz wrote in his journal that “almost everything” about the hotel deal had “an immoral cast.” But as the ghostwriter he was “trying hard to find my way around” behavior that he considered “if not reprehensible, at least morally questionable.”

Many tall tales that Trump told Schwartz contained a kernel of truth but made him out to be cleverer than he was. One of Trump’s favorite stories was about how he had tricked the company that owned Holiday Inn into becoming his partner in an Atlantic City casino. Trump claimed that he had quieted executives’ fears of construction delays by ordering his construction supervisor to make a vacant lot that he owned look like “the most active construction site in the history of the world.” As Trump tells it in “The Art of the Deal,” there were so many dump trucks and bulldozers pushing around dirt and filling holes that had just been dug that when Holiday Inn executives visited the site it “looked as if we were in the midst of building the Grand Coulee Dam.” The stunt, Trump claimed, pushed the deal through. After the book came out, though, a consultant for Trump’s casinos, Al Glasgow, who is now deceased, told Schwartz, “It never happened.” There may have been one or two trucks, but not the fleet that made it a great story.