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As a book publishing phenomenon, young adult literature entered the decade like a lion. At the beginning of the 2010s, a generation that had grown up obsessed with Harry Potter and other middle-grade fantasy series decided it wasn’t that interested in adult literary fiction, with its often lackadaisical plotting and downbeat endings. YA stood ready to supply them with plenty of action, cliffhangers, supernatural beings, mustache-twirling bad guys, and true love. But now, at decade’s end, YA seems to be eating itself alive.

By 2010, Stephenie Meyers’ Twilight had already proven that a multivolume YA franchise with a romantic triangle and lashings of paranormal brooding could be a virtual license to mint money, especially when the inevitable movie deal came along. Then the 2012 film version of Suzanne Collins’ The Hunger Games, a series already enormously popular in print, was a hit in theaters, adding dystopian yarns to the roster of blockbuster YA themes. To distinguish themselves in an increasingly crowded field, the genre’s characters sported ever-stranger and even outright gimmicky special powers—the ability to manipulate iron or kill with a touch or turn into a bee—and they wrestled with societies that dictated whom they married, segregated them into factions based on temperament, or subjected them to surgery that eradicated their ability to love. Dystopia was a trenchant genre for middle-class kids who grew up heavily surveilled by parents and social media, as well as pressured to vie for their spot in a relentless meritocracy starting from grade school.

But perhaps the most emblematic event in YA during the 2010s was less high-profile: the founding of Full Fathom Five, a “content creation company,” by James Frey, whose bestselling 2003 memoir, A Million Little Pieces, had been exposed as having been substantially fabricated. In a 2010 article for New York magazine, Suzanne Mozes described how Frey recruited her and other graduate writing program students at Columbia to work for Full Fathom Five writing assorted YA series based on highly commercial premises with an eye toward attracting movie producers. In return, the young hopefuls received a flat rate of $250 and the promise of a cut of any future proceeds, along with no rights to their own creations and an Orwellian NDA.

The most successful of these products, 2011’s I Am Number Four, was written by Frey and Jobie Hughes under the pseudonym Pittacus Lore and was adapted by DreamWorks in 2011. At one point, Full Fathom Five employed as many as 28 writers who were cranking out boilerplate YA novels for minimal compensation. Frey’s venture, which still exists, is a YA factory whose current properties have expanded to include adult romance novels and a middle-grade series called The Fart Squad.

The young adult genre produced many books of genuine literary merit during the 2010s, from John Green’s The Fault in Our Stars to Frances Hardinge’s The Lie Tree, which won the 2015 Costa Book of the Year Award against a field of adult novels. But titles like those were not what drew Frey and other carpetbaggers to YA during the gold rush that followed Twilight and The Hunger Games. A large portion of the genre has always relied on formulaic story lines and high volume, going back to “Carolyn Keene,” the collective pseudonym of the many contracted authors hired to write Nancy Drew mysteries from the 1930s onward. It just wasn’t until the 2010s that this kind of fiction showed itself capable of selling in the millions of copies. Veronica Roth’s Divergent trilogy, set in a post-apocalyptic Chicago, sold 6.7 million books between 2011 and 2013. Copycats proliferated. Bonanzas are rare in book publishing, but this was a bona fide one.

Adult readers were a significant source of the boom. In 2012, Publishers Weekly reported on a study showing that 55 percent of books intended for a YA audience (readers aged 12 to 17) were bought by adults, and 78 percent of those purchases were for the buyer’s own reading. The largest segment of this group, 30- to 44-year-olds, were responsible for 28 percent of YA book sales. And while most of these buyers expressed no interest in joining a traditional book club, a majority also described themselves as very involved in online social networks, from purpose-built readers’ sites like Goodreads to general-interest platforms like Twitter. Science fiction and fantasy readers might have been the first genre fans to congregate online, but YA fans and influencers took to social media with an enthusiasm and alacrity that was head-spinning, but far from surprising. Many of them had roots in Harry Potter fandom from way back.

At first, the sophisticated networking of YA’s adult fans seemed an unmitigated good. Librarians and bloggers joined ordinary readers online to share recommendations and stoke the hype for upcoming releases from such favorite authors as Cassandra Clare, Rainbow Rowell, Leigh Bardugo, and Maggie Stiefvater. Word of mouth has always been the most effective way to market fiction, and this was word of mouth on steroids. In 2017, the online YA community even detected and exposed a fraudulent New York Times “bestseller,” Handbook for Mortals by Lani Sarem, a former actress, screenwriter, and self-described “rock ’n’ rolly gypsy” whose debut novel mysteriously appeared at the top of the newspaper’s YA bestseller list—despite the fact that nobody in the community seemed to have heard of it before, let alone read it. Online sleuths, many of them YA authors themselves, soon got to the bottom of this surprise “hit.” In a move worthy of Frey, Sarem had gamed the Times’ list by preordering copies of her essentially self-published novel in bulk. Her ultimate goal? A movie deal, of course.

She might have spared herself the trouble and expense. By the late 2010s, several big- and small-screen adaptions of hugely popular YA fantasy and science fiction series by Roth, Clare, Rick Yancey, and Pittacus Lore himself had bombed at the box office. Film versions of stand-alone books with realistic contemporary settings like The Fault in Our Stars and Love, Simon did better, but they didn’t lend themselves to blockbuster franchises like Twilight and The Hunger Games. Meanwhile, hopeful authors’ attempts to surf the trends of the moment flooded the YA publishing world.

At the same time, people in and outside the book publishing world became concerned with how white the industry was (and continues to be). How could such a monocultural workforce serve a market (young people) of history-making diversity? Publishing professionals founded initiatives like We Need Diverse Books, a nonprofit that issues grants to authors and, crucially, college students interested in book publishing internships but who can’t afford to work for free in New York City.

It was a change fueled by the most vocal online reader community the industry had ever known. In 2015, Dutch writer Corinne Duyvis started the #ownvoices hashtag on Twitter—which had increasingly become the primary hub of conversations about the genre—to “recommend kidlit about diverse characters written by authors from that same diverse group.” The Hate U Give by Angie Thomas, a novel about black victims of police violence that was fortuitously published a few months after the 2016 election, became a steady bestseller, as did Tomi Adeyemi’s Children of Blood and Bone, a refreshing fantasy rooted in African mythology published the following spring.

The impulse that led to these and other worthy enterprises, however, is vulnerable to being twisted to less-salutary ends on platforms that foster cliques, vendettas, and self-righteous posturing. In the past two years, online networks of YA authors and readers—mostly female adults—have been convulsed with assorted scandals and controversies that have left many outside observers with the impression that “YA Twitter” is hopelessly “toxic.” Bloggers and Twitter pundits pilloried 2017’s The Black Witch, a debut young adult fantasy novel by Laurie Forest, for its purported “racism.” That criticism proved unconvincing—even to teen readers, who made the book a success and reviewed it enthusiastically on Amazon—but few of those weighing in on the controversy bothered to point out instead how listlessly predictable The Black Witch is, with the usual high-born heroine confronting an unjust world while embroiled in the usual bad boy–good boy love triangle. It didn’t quite seem worthy of the energy adult readers devoted to fighting over it.

Meanwhile, the Guardian reports that YA authors in the U.K. are panicking over an ongoing slump in sales that in February reached the lowest point in 11 years. The American children’s bestseller lists, studded with YA titles in the mid-2010s, are now evermore dominated by innocuous middle-grade series like Captain Underpants, the Dork Diaries, countless James Patterson titles aimed at a middle school readership, Rick Riordan’s mythological boys’ adventure stories, and the awe-inspiring juggernaut that is Jeff Kinney’s Diary of a Wimpy Kid series—the latest installment of which is, at the time I write this, the week’s bestselling book of any genre. If you snorted at Full Fathom Five’s The Fart Squad, well, this just might be another of those occasions when James Frey gets the last laugh.

Read the rest of Slate’s coverage of the end of the decade.