‘Rich Kids’ Infamous On Tumblr, And Now By Book

They flaunt their Rolls-Royces, bikini bodies and priceless art. Their jets, yachts and fat stacks of cash, rolled into $10K bundles. They pop bottles of Dom Perignon poolside, sunbathing outside their sprawling mansions—from Dubai to Palm Beach to the East End—before hitting the hottest nightclubs, or dropping $40,000 on a shopping spree without blinking.

They are unapologetic. They have no shame.

And they are all under the age of 30.

These are the Rich Kids of Instagram—the real-life inspiration behind author Maya Sloan’s newest book of the same name, co-created with the anonymous founder of the popular, eponymous Tumblr blog. The glamorous lives these heirs and heiresses lead are almost unbelievable, Ms. Sloan said, but with a careful eye, it is easy to see a dark, lonely underbelly stirring underneath the surface.

“These kids are young and they have a shitload of money. And, a lot of times, they don’t have any parental guidance,” Ms. Sloan said during a telephone interview last week from her residency in Jack Kerouac’s old home in Florida. “Their parents are über-busy, and the kids are left to their own devices. I think, ‘Okay, if I was 18 and I had millions of dollars, access to a private jet, I don’t know, I might do something crazy and post a picture.’ People love to hate it. And I knew before the book came out that there were going to be a lot of haters.”

The recently published, 339-page book set in the Hamptons and Manhattan—its cover depicting a $100 bill with a line of textured cocaine running down the center of Benjamin Franklin’s visage—chronicles the lives of seven fictional narrators, whose unique voices interchange between chapters, each divided by an illustrated Instagram picture drawn by Danish artist Thomas Warming, Ms. Sloan’s husband.

A collaboration of this kind—between an author, illustrator and social media website—is unprecedented, according to Ms. Sloan. She had never heard of Rich Kids of Instagram before receiving the pitch a year ago from its anonymous creator, who said he founded the website on a whim.

“It was a couple years ago on a summer night, after a few bottles of wine, that we came up with the idea,” the creator of Rich Kids of Instagram said in an email on Monday afternoon. “We jumped on Tumblr and then passed it around to some friends. Not thinking much of it, actually.”

The website took off. Every month, Rich Kids of Instagram attracts about half a million visitors, he reported, who view curated, daily submissions from the children of the 1 percent. “We don’t kiss and tell,” he said of the selection process, which has yielded images of a baby pet cheetah in Dubai, or a Leonardo da Vinci painting nestled in the backseat of a Hamptons-bound Ferrari, now infamous in web culture.

Rich Kids of Instagram is unbridled entertainment, voyeuristic and compelling, he said, but “maddening” for some. To the naysayers, he replies, “Sigh.”

“We’re proud [of the book],” he said. “The cover is amazing—that coke really pops, doesn’t it? I think it came together just like we wanted.”

After agreeing to the deal, Ms. Sloan and Mr. Warming enlisted the help of two “informants”—one, the son of a media mogul and, the other, a royal—and hit the Hamptons hard. They crashed exclusive parties and a handful of annual events, including the Hampton Classic in Bridgehampton and Authors Night in East Hampton, where Ms. Sloan rubbed elbows with actor Gwyneth Paltrow and author Jay McInerney. Even a visit to the local supermarket was far from ordinary, considering actor Gerard Butler and his family were in the next aisle over, Mr. Warming recalled.

“This is what you see in the movies. This is what you see on TV,” Ms. Sloan said. “And then you see it up close and see some of those things are real. I find it really ironic that I’m so far from that world.”

Growing up in Oklahoma City, Ms. Sloan lived with her two academic parents and dreams of being a writer. Her first novel, “High Before Homeroom,” exploring teenage popularity and drug use, was published in 2010, followed by the 2012 memoir “Redefining Diva” that she ghostwrote for Broadway star Sheryl Lee Ralph. It caught the attention of Kendall and Kylie Jenner, the youngest sisters of the Kardashian clan, who enlisted Ms. Sloan to write their dystopian young adult novel “Rebels: City of Indra.”

This line of work has come as a complete shock to Ms. Sloan, she said, who has virtually zero background in celebrity culture or extreme wealth. But what the 37-year-old does possess is an understanding of human nature and the ability to translate unique perspectives onto the page—with a sense of compassion.

“The last thing I wanted to do was another book that makes fun of rich people. It’s too easy and it’s been done a million times,” she said. “Innately, there’s a commentary when you’re dealing with class issues—saying the things no one wants to say. And, yeah, these characters do awful things. But on some level, I care about all of them. And I understand where they are coming from. But this is fiction. This is not real. If these rich kids read this book and say, ‘This is about me’—it’s not.”

She laughed, and continued, “In a lot of ways, I think the site is more for the kids themselves, to show off to each other. And the world at large is just secondary.”

For more information on Rich Kids of Instagram, visit richkidsofinstagram.tumblr.com.