As he has prepared to be named the Republican nominee for president, Donald Trump has not read any biographies of presidents. He said he would like to someday.

He has no time to read, he said: “I never have. I’m always busy doing a lot. Now I’m more busy, I guess, than ever before.”

Trump’s desk is piled high with magazines, nearly all of them with himself on their covers, and each morning, he reviews a pile of printouts of news articles about himself that his secretary delivers to his desk. But there are no shelves of books in his office, no computer on his desk.

Presidents have different ways of preparing to make decisions. Some read deeply, some prefer to review short memos that condense difficult issues into bite-size summaries, ideally with check-boxes at the bottom of the page. But Trump, poised to become the first ­major-party presidential nominee since Dwight Eisenhower who had not previously held elected office, appears to have an unusually light appetite for reading.

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He said in a series of interviews that he does not need to read extensively because he reaches the right decisions “with very little knowledge other than the knowledge I [already] had, plus the words ‘common sense,’ because I have a lot of common sense and I have a lot of business ability.”

Trump said he is skeptical of experts because “they can’t see the forest for the trees.” He believes that when he makes decisions, people see that he instinctively knows the right thing to do: “A lot of people said, ‘Man, he was more accurate than guys who have studied it all the time.’ ”

Trump’s approach to understanding complex issues and reaching decisions is not unique in the annals of the presidency. Historians who have studied presidential styles depict a divide between men such as President Obama or presidents Bill Clinton, George H.W. Bush, Jimmy Carter and Richard Nixon, who were given to reading extensively ahead of important decisions, and presidents Eisenhower, Ronald Reagan and George W. Bush, who preferred to have issues presented to them in short memos or orally.

“We’ve had good presidents of both styles,” said David Greenberg, a presidency historian at Rutgers University. “There’s a kind of danger when intellectuals and journalists see these presidents who don’t read much and scorn them as being not so swift. There’s some political prejudice there on the part of liberals against these business types who have a different executive style.”

Trump’s approach goes beyond the chief executive manner of Reagan or the younger Bush. “We’ve had presidents who have reveled in their lack of erudition,” said Allan Lichtman, a political historian at American University, citing Warren Harding and Lyndon Johnson as leaders who scoffed at academics and other experts. “But Trump is really something of an outlier with this idea that knowing things is almost a distraction. He doesn’t have a historical anchor, so you see his gut changing on issues from moment to moment.”

One day last month, Trump had a visit from a delegation of prominent executives in the oil, steel and retail industries, and one of the executives told Trump that the Chinese were taking advantage of the United States. “He said, ‘I’d like to send you a report,’ ” Trump recalled. “He said, ‘I’d love to be able to send you’ — oh boy, he’s got a lengthy report, hundreds of pages. . . . I said, ‘Do me a favor: Don’t send me a report. Send me, like, three pages.’ ”

Trump said reading long documents is a waste of time because he absorbs the gist of an issue very quickly. “I’m a very efficient guy,” he said. “Now, I could also do it verbally, which is fine. I’d always rather have — I want it short. There’s no reason to do hundreds of pages because I know exactly what it is.”

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As the reality of the nomination became clear, Trump said he thought about reading up, maybe dipping into a biography of a president, “but I don’t have much time,” he said. “I have so little time.”

Trump has no shortage of strong opinions even about books he has not read. He told The Washington Post that he has not read four biographies written about him, yet he called three of the authors of those books “lowlifes,” and he sued one of them for libel.

Trump’s attitude toward experts and deep study reminds some historians of George W. Bush’s oft-stated skepticism about experts, whether they studied climate change, the roots of poverty or the causes of religious conflicts.

“It’s certainly legitimate to desire a reflective person in the Oval Office, but the absence of that isn’t inherently dangerous,” Greenberg said. “In Trump’s case, his attitude toward reading is hardly unprecedented, but when you combine it with the vulgarity and the authoritarian style, it shows a locker-room, business-world machismo that pervades his persona.”

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On the other hand, the appearance of too much deliberation in a president can suggest indecisiveness.

“You’ve got to make decisions based on information and not emotions,” Obama told The Post at the start of his presidency. Scholars of the presidency described Obama’s method — extensive reading as well as meeting after meeting — as deliberate and cautious. Critics have called his style “dithering,” as former vice president Richard B. Cheney put it early in Obama’s first term.

Many presidents have had an academic bent. Woodrow Wilson was president of Princeton University before he became governor of New Jersey, and Eisenhower served as president of Columbia University after commanding Allied forces in Europe in World War II. Nixon wrote foreign-policy tomes, and Obama taught law at the University of Chicago.

There is no clear correlation between studious presidents and success in the office, historians said. Carter and Nixon shared “a kind of obsessional quality,” Greenberg said. Carter famously spent time scheduling the use of the White House tennis courts, and Nixon labored over lists of invitees to state dinners, “suggesting problems with their executive decision-making styles,” he said.

Trump said he has mastered the world of books; working with co-writers, he has published more than a dozen, most of them autobiographical or in the business-advice genre.

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Presidential nominees, like many candidates for public office, are often asked about their reading habits, and they usually have a few impressive titles ready for curious reporters. Not having a strong reading list in mind has caused some candidates a bit of embarrassment. In 2008, when TV anchor Katie Couric asked then-Alaska Gov. Sarah Palin, who had just been named John McCain’s vice-

presidential running mate, what newspapers and magazines she read, Palin stumbled: “I’ve read most of them . . . ” She was asked which ones specifically. “Um, all of them, any of them that have been in front of me all these years,” she said. “I have a vast variety of sources where we get our news, too. Alaska isn’t a foreign country.”

Trump, in contrast, offered The Post no titles when asked about books on presidents that have made an impression on him. He has, however, offered other news organizations a taste of his reading preferences. He told the Hollywood Reporter last month that he was reading “Unlikeable: The Problem With Hillary,” a highly critical book about his opponent by Edward Klein, as well as rereading one of his favorites, “All Quiet on the Western Front,” the classic German novel about World War I that was one of the first intimate portraits of the anguish and psychological terror of modern combat.

In his 2006 book, “Trump 101: The Way to Success,” Trump recommended, in addition to his own autobiography, the longtime bestseller “The Power of Positive Thinking,” by Norman Vincent Peale, who was Trump’s minister through the early part of his life; classics such as Sun Tzu’s “The Art of War”; William Manchester’s biography of Winston Churchill; and essays by Ralph Waldo Emerson and Albert Einstein.

In 2011, Trump listed 20 books about China that he said had helped him understand the country, its politics and its people. He told Xinhua, the official Chinese news agency, that he had read “hundreds of books about China over the decades,” including works by Henry Kissinger and American and Chinese journalists and novelists.

Some historians have argued that people who read lots of books do not necessarily make the best presidents, though many of the greatest presidents, such as George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt — were learned men who read deeply in history, philosophy and religion.

The best presidents “all had a compass other than their urges of the moment,” Lichtman said. “Franklin Roosevelt wasn’t a great intellect, but he knew his history, and he had an anchor. A president’s success stems from the values and character they bring to the office. Kennedy called it ‘practical vision,’ and no decision-making model can compensate for that.”