President Trump and Kim Jong-un of North Korea will hold the first-ever meeting between leaders of their two countries on Tuesday morning in Singapore, carrying with them hopes to end seven decades of hostility and the threat of a nuclear confrontation.

At stake is the American goal of ridding North Korea of its nuclear arsenal, Mr. Kim’s desire to remove American weapons from the Korean Peninsula and to be recognized as a player on the world stage, and international hopes to ease the North’s poverty, provocations and extreme isolation.

The talks begin at 9 a.m. on Tuesday — 9 p.m. Eastern on Monday — and could even open the way to an official end to the Korean War, which concluded in 1953 with a truce but never a peace treaty. South Korea will not be at the table, nor will China, the North’s most crucial backer.

The summit meeting is the most prominent moment yet in international affairs for both Mr. Trump and Mr. Kim. Not long ago, they were better known for threatening each other’s countries with destruction than for peace overtures.

Here’s what has happened so far:

• Both leaders arrived in Singapore on Sunday, Mr. Trump fresh from a clash with American allies at the Group of 7 meeting in Canada, and Mr. Kim with a little travel help from his Chinese allies.

• Just hours before the meeting was to begin, American and North Korean officials continued to scramble behind the scenes, searching for areas of agreement on issues that have eluded consensus for decades.

• With thousands of journalists from around the world congregating in Singapore, Mr. Kim and his entourage left his hotel on Monday night, and the media scrambled before catching up with him at the Marina Bay Sands hotel.

As the meeting approached, American and North Korean officials worked to hammer out a joint statement the two leaders might make at the close of their talks. But it was unclear that they could do more than reach a broad, general agreement on tough questions like nuclear disarmament.

Mr. Trump told other Asian leaders he was confident about the prospects for the meeting, but the two sides may have fundamentally understandings of some crucial issues, like “denuclearization” of the peninsula.

To American officials, that has meant Pyongyang giving up its atomic weapons program, but North Korea has suggested that it would also mean a reduction or even elimination of American arms in the region. The vast scope of North Korea’s atomic program means ending it would be the most challenging case of nuclear disarmament in history.

It is also unclear whether the Trump administration would go further than its predecessors in assuring North Korea that, in exchange for concessions, it would be secure from attack by the United States.

The meeting holds the risk of exposing unbridgeable gaps, leaving both sides fuming, with little to show for all the fanfare.

[Richard M. Nixon took crib notes to his historic meeting with Mao Zedong in 1972. What should President Trump remember when he meets Mr. Kim?]

Mr. Kim arrived for the meeting on Sunday not on one of his country’s aircraft, but aboard an Air China jumbo jet — an American-made Boeing 747.

The choice of a plane supplied by China, North Korea’s closest ally, highlighted the paucity of resources in Mr. Kim’s country. The Air China jet is newer, bigger, more comfortable — and, aviation experts say, more reliable — than Mr. Kim’s Soviet-made jets.

Other members of the North Korean team arrived, along with Mr. Kim’s limousine, on North Korean-owned aircraft.

But Mr. Kim rode in a specially outfitted 747 that has been used to carry top Chinese officials. His usual plane, an Ilyushin-62, was built around 1980, and the type has been out of production since the mid-1990s.

“The president and the entire U.S. team are looking forward to tomorrow’s summit,” Mr. Pompeo said in a statement on Monday.

That team includes, among others, Mr. Pompeo; John F. Kelly, the White House chief of staff; John R. Bolton, the national security adviser; and Matthew Pottinger, the National Security Council’s top Asia hand.

The administration also recruited Sung Y. Kim, a seasoned North Korea negotiator currently serving as the American ambassador to the Philippines.

Among the North Koreans attending the summit meeting is Kim Yong-chol, a former leader of North Korea’s main spy agency, who now serves as a vice chairman of the ruling Workers’ Party. He had visited Mr. Trump at the White House on June 1, delivering a personal letter from Mr. Kim.

Ri Yong-ho, the foreign minister, and Choe Son-hui, a vice foreign minister, have haggled with the United States for decades over their country’s nuclear weapons program. Ms. Choe called Vice President Mike Pence “ignorant and stupid” last month, briefly jeopardizing the summit meeting. No Kwang-chol became minister of the People’s Armed Forces during a recent reshuffle of the top military leadership.

Kim Yo-jong, Mr. Kim’s only sister, has been an important face of North Korea’s recent diplomatic overtures. Mr. Kim sent her to South Korea in February to invite Mr. Moon to a summit meeting. She is in charge of the party’s Department of Propaganda and Agitation, one of the most powerful agencies in North Korea.

The summit meeting in Singapore is on track after some fraught on-again, off-again moments.

Where will the leaders meet? Who will be there? What’s on the agenda?

We’ve put together a primer to the high-stakes talks that breaks down the key players and the key issues.

About 2,500 journalists from around the world have registered for official credentials to cover the Trump-Kim summit meeting, according to Singapore’s Ministry of Communications. That might be an understatement — Secretary of State Mike Pompeo said closer to 5,000 were in Singapore to document the meeting.

Foreign journalists are working out of a large building usually reserved for Formula One racers and their pit crews. At a Marriott hotel where the White House press corps is stationed, television crews line up along an outside patio, as correspondents give their on-camera reports.

All three of the major American cable news networks are anchoring their nightly news programs from Singapore. North Korean experts are in high demand, with many of them signing contracts to appear as exclusive commentators on the talks.

Camera crews have staked out the St. Regis Hotel, where Mr. Kim is staying, although he eluded the media for most of Monday. In the evening, his entourage left the hotel and the news media frantically tried to figure out where he was going, before catching up to him at another hotel.

As if teasing the world’s jouranlists, Singapore’s foreign minister, Vivian Balakrishnan, tweeted a selfie with the North Korean leader with the hashtag #guesswhere?

The White House press corps — more than 350 reporters — filed dispatches from two floors of a glitzy ballroom at the Marriott Singapore South Beach, with hundreds of curved metal cylinders hanging from the ceiling. “This is the most dramatic WH press file I’ve been in,” David Nakamura, a reporter for The Washington Post, wrote on Twitter.

Reporters chased anyone they hoped could give them a shred of information. At one point on Sunday, journalists even swarmed one of their own, albeit a reporter from North Korea, who fled to his hotel.

While most foreign news outlets began wall-to-wall coverage on Sunday, the North Korean media waited until Monday to report that Mr. Kim had arrived in Singapore a day earlier and met with Singapore’s prime minister.

On social media, analysts reading the tea leaves noted that the Korean Central News Agency, KCNA, had mentioned that Mr. Kim flew to Singapore on a “Chinese plane.”

“By reporting that he landed in Singapore on ‘Chinese plane’ highlights not only historic nature of his journey beyond Korea & #China but also signals to his people that DPRK-Chinese relations have been restored,” tweeted Jean H. Lee, a former Associated Press bureau chief in Pyongyang and now a global fellow at the Woodrow Wilson Center in Washington.

Perhaps more significantly, KCNA also reported that North Korea’s leader hoped to be “building a permanent and durable peacekeeping mechanism on the Korean Peninsula.” as well as “the denuclearization of the Korean Peninsula and other issues of mutual concern.”