Riding in a motorcade in Lima, Peru, shortly after the 2016 election, President Barack Obama was struggling to understand Donald J. Trump’s victory.

“What if we were wrong?” he asked aides riding with him in the armored presidential limousine.

He had read a column asserting that liberals had forgotten how important identity was to people and had promoted an empty cosmopolitan globalism that made many feel left behind. “Maybe we pushed too far,” Mr. Obama said. “Maybe people just want to fall back into their tribe.”

His aides reassured him that he still would have won had he been able to run for another term and that the next generation had more in common with him than with Mr. Trump. Mr. Obama, the first black man elected president, did not seem convinced. “Sometimes I wonder whether I was 10 or 20 years too early,” he said.

In the weeks after Mr. Trump’s election, Mr. Obama went through multiple emotional stages, according to a new book by his longtime adviser Benjamin J. Rhodes. At times, the departing president took the long view, at other points, he flashed anger. He called Mr. Trump a “cartoon” figure who cared more about his crowd sizes than any particular policy. And he expressed rare self-doubt, wondering whether he had misjudged his own influence on American history.

Set to be published next week by Random House, Mr. Rhodes’s memoir, “The World as It Is,” offers a peek into Mr. Obama’s tightly sealed inner sanctum from the perspective of one of the few people who saw him up close through all eight years of his presidency. Few moments shook Mr. Obama more than the decision by voters to replace him with a candidate who had questioned his very birth.

Mr. Rhodes served as Mr. Obama’s deputy national security adviser through some of the most consequential points of his presidency, including decisions to authorize the raid that killed Osama bin Laden, send more troops to Afghanistan, pull most troops out of Iraq, restore diplomatic relations with Cuba, seal a nuclear agreement with Iran, intervene militarily in Libya and refuse to intervene militarily in Syria.

But his book offers a new window, if only slightly cracked open, into the 44th president’s handling of Russia’s intervention in the 2016 election to help Mr. Trump get elected and the aftermath.

In handing over power to someone determined to tear down all he had accomplished, Mr. Obama alluded to “The Godfather” mafia movie: “I feel like Michael Corleone. I almost got out.”

Mr. Rhodes describes the reaction of foreign leaders. Prime Minister Shinzo Abe of Japan apologized for breaching protocol by meeting with Mr. Trump at Trump Tower in Manhattan after the election. Mr. Obama urged Prime Minister Justin Trudeau of Canada to take on a more vocal role defending the values they shared.

Chancellor Angela Merkel of Germany told Mr. Obama that she felt more obliged to run for another term because of Mr. Trump’s election to defend the liberal international order. When they parted for the final time, Ms. Merkel had a single tear in her eye. “She’s all alone,” Mr. Obama noted.

And yet despite criticism even from former advisers to Mr. Obama, Mr. Rhodes offers little sense that the former president thought he could have done more to counter Russian involvement in the election. Mr. Obama had authorized a statement to be issued by intelligence agency leaders a month before the election warning of Russian interference, but was thwarted from doing more because Senator Mitch McConnell of Kentucky, the Republican leader, refused to go along with a bipartisan statement.

Mr. Rhodes called Mr. McConnell’s refusal “staggeringly partisan and unpatriotic.” But Mr. Obama, whose Supreme Court nomination had been blocked by Mr. McConnell for months, seemed less surprised.

“What else did you expect from McConnell?” he asked. “He won’t even give us a hearing on Merrick Garland.”

Still, in preparatory sessions before meetings with the news media before the election, aides pressed Mr. Obama to respond to criticism that he should speak out more about Russian meddling. “I talk about it every time I’m asked,” he responded. “What else are we going to do? We’ve warned folks.”

He noted that Mr. Trump was already claiming that the election would be manipulated if Hillary Clinton won. “If I speak out more, he’ll just say it’s rigged,” Mr. Obama said.

Mr. Rhodes writes that neither he nor Mr. Obama knew at that time that there was an F.B.I. investigation into contacts between Mr. Trump’s campaign and Russia, despite Mr. Trump’s recent unsubstantiated claims that the departing president placed a “spy” or multiple spies in his campaign.

Mr. Rhodes writes he did not learn about the F.B.I. investigation until after leaving office, and then from the news media. Mr. Obama did not impose sanctions on Russia in retaliation for the meddling before the election because he believed it might prompt Moscow into hacking into Election Day vote tabulations. Mr. Obama did impose sanctions after the election but Mr. Rhodes’s suggestion that the targets include President Vladimir V. Putin was rebuffed on the theory that such a move would go too far.

Mr. Obama and his team were confident that Mrs. Clinton would win and, like much of the country, were shocked when she did not. “I couldn’t shake the feeling that I should have seen it coming,” Mr. Rhodes writes. “Because when you distilled it, stripped out the racism and misogyny, we’d run against Hillary eight years ago with the same message Trump had used: She’s part of a corrupt establishment that can’t be trusted to bring change.”

On election night, Mr. Obama spoke by telephone with Cody Keenan, his chief speechwriter, and Mr. Rhodes to figure out what he should say. Mr. Rhodes asked if he should offer reassurance to allies. “No, I don’t think that I’m the one to tell them that,” the president said.

The next day, Mr. Obama focused on cheering up his despondent staff. At one point, he sent a message to Mr. Rhodes saying, “There are more stars in the sky than grains of sand on the earth.”

But days later, Mr. Obama seemed less sanguine. “I don’t know,” he told aides. “Maybe this is what people want. I’ve got the economy set up well for him. No facts. No consequences. They can just have a cartoon.”

He added that “we’re about to find out just how resilient our institutions are, at home and around the world.”

The day Mr. Obama hosted Mr. Trump at the White House after the election seemed surreal. Mr. Trump kept steering the conversation back to the size of his rallies, noting that he and Mr. Obama could draw big crowds, but Mrs. Clinton could not, Mr. Rhodes writes.

Afterward, Mr. Obama called a few aides to the Oval Office to ruminate on the encounter. “I’m trying to place him in American history,” he said.

“He peddles” bull, Mr. Rhodes answered. “That character has always been part of the American story. You can see it right back to some of the characters in Huckleberry Finn.”

“Maybe,” Mr. Obama answered, “that’s the best we can hope for.”

New York Times