Back in 1970, when the first New York City Marathon was run, it was something very different than we know today: four laps around Central Park, which was hardly the pastoral jewel that New Yorkers now know and love. It was marred by rampant vandalism, drugs were sold openly at Bethesda Fountain and graffiti defaced most of its buildings. The park’s dangers were so well known that any mention of a nighttime stroll there was a surefire laugh-line on the Johnny Carson show.

Yet the race directors, Fred Lebow and Vince Chiappetta, knew that Mayor John Lindsay was eager to restore the park to its former glory, so they put together the inaugural New York City Marathon that September. The humble race attracted just 127 starters (and only one woman, Nina Kuscsik) but nevertheless established an important theme — revival and resilience — that has run through all subsequent N.Y.C. Marathons.

So in 1976 when George Spitz, a civil servant and runner, proposed a marathon through all five boroughs, the time seemed almost right — if daunting. “A race like that could cost $15,000,” Mr. Lebow pointed out. “Where are we going to get that kind of money?” But Mr. Spitz won over Manhattan’s borough president, Percy Sutton, who persuaded Lewis and Jack Rudin, brothers from a prominent real estate family, to put up $25,000. That was the turning point.

In a meeting with Mayor Abe Beame, Mr. Spitz, Mr. Lebow and I pitched the marathon as a one-time attraction like the Bicentennial’s “tall ships” event. We told the mayor a five-borough race might help revive a nearly bankrupt, crime-ridden city. He agreed.

Mr. Lebow, a Romanian-born Holocaust survivor who had been churning out knockoffs in the garment district, now found his life’s calling. He asked the soft-spoken Ted Corbitt, an Olympic marathoner and first president of the New York Road Runners Club, to design the course with a finish in Central Park.

Like every Big Apple promoter, Mr. Lebow needed star power to gain media attention. Fortunately, I was able to get commitments from Frank Shorter and Bill Rodgers, America’s two top distance men. Mr. Shorter quipped that he was coming “to see if the police could close down New York City’s streets for a footrace.” We also managed to quietly give them each $3,000 — those were the “shamateurism” days, when such payments were commonplace but not spoken about.

Soon excitement began growing among other recreational runners and even non-runners. Kenneth Gibson, the mayor of Newark, entered the race, as did Jacques d’Amboise, the charismatic ballet star, who sent a postcard from Paris updating me on his training: “Ran 10 miles in the Bois de Boulogne after our performance tonight. It was beautiful.”

Mr. Shorter stayed at my house, and we watched the third Jimmy Carter-Gerald Ford presidential debate together several nights before the race. I couldn’t understand why he was shivering even though bundled up in a heavy parka. I was a regular long-distance runner, but I had never met anyone with only 2 percent body fat.

On marathon morning in 1976, we headed early to the start at the Verrazzano Bridge. In my journal, I described it as a Felliniesque spectacle: “Two thousand of us waited for the start, helicopters hovered overhead. With all the noise, I never heard the starter’s gun, but began running when everyone else did.”

After that no one — absolutely no one — questioned whether the citywide marathon should be run again. We all knew we had an instant hit on our hands. Through the years, most New Yorkers have come to regard marathon day as one of the best, most inclusive days in the life of the city.

Crowds line almost every foot of the course, celebrating and cheering the participants. Everyone seems to know someone who is running. And for some reason, the crime rate always dips on marathon Sunday.

But there have been challenges. In 2001, 54 days after the terrorist attacks of 9/11, the marathon took on outsize importance. New Yorkers cheered on in an act of resolution, defiance and resilience. With 2,800 police officers on duty and a no-fly zone overhead, the race was promoted under a newly adopted slogan, United We Run.

Chris Bilsky, a runner and a nurse at Memorial Sloan Kettering Cancer Center, explained the marathon’s significance that year to a New York Times reporter. In her training, Ms. Bilsky said, “Many times, I couldn’t stop crying when I ran, but I feel a duty to stand with 30,000 runners and be united.” She ran the race with the names of three friends written on her arms — all lost in the World Trade Center attacks.

But the marathon would not be canceled until 2012, as the city tottered from another heavy blow, the aftermath of Hurricane Sandy. Mayor Michael R. Bloomberg and race organizers had hoped the marathon could rally the city’s spirits. But with scores dead, neighborhoods still under water and 40,000 people homeless, many viewed the event as too much, too soon. On the Friday evening before the marathon, the race was called off.

A year later — and seven months after the Boston Marathon bombings of April 2013 — the marathon returned to New York. While some areas were still recovering from Sandy, and a huge security effort was necessary after Boston, the city was desperate for a celebration.

It got one. Despite the cold, spectators witnessed the largest marathon field ever assembled. More than 50,000 runners finished the race.

Now again, we face another renewal. A mass road race at the height of the pandemic last year was never considered. Recently I talked with Ms. Bilsky, the nurse who honored those fallen first responders 20 years ago. Now 58, she won’t be running this year, owing to an ankle injury, but she will join the celebration. “Covid took our city away from us,” she said. “If there’s anything that can bring it back together, it’s the marathon.”