“Charlie and the Chocolate Factory?”

“No.”

“How about The Phantom Tollbooth? I love that book.”

“No,” Elliott says. He holds out a slender volume: Who Would Win? Ultimate Pterosaur Rumble.

“We just read that,” I say, almost crying.

“I know,” he says, with what passes for compassion in a 4-year-old boy. Before we start in on Pterosaur Rumble, he predicts with some confidence that Quetzalcoatlus will take the final prize, and for the 17th time since we bought the book three days ago, he will be right.

My son Elliott came across the Who Would Win? books a year ago on a spinning rack at a nearby library. Since then, they have accounted for more than half of the reading we do together, and a good part of the “reading” he does by himself. Even though we’ve read all 31 books in the series (so far), Elliott keeps demanding we go back to the library, as if they might grow on the rack like combative fruit.

Most of the books are slim paperbacks with more pictures than text. They pit various animals against each other: Killer Whale vs. Great White Shark; Lion vs. Tiger; Grizzly Bear vs. Polar Bear. Each describes its fighters in simple but scientifically accurate terms, and then hypothesizes an encounter in the wild that inevitably, sigh, leads to conflict.

There’s also the Ultimate Rumble subseries, in which 16 animals in the same habitat or of the same species—ocean creatures; pterosaurs—fight in a single-elimination tournament until only one is left. Where did the author come up with that?

“I was watching the Sweet 16 tournament in a bar,” Jerry Pallotta told me.

I had doubted that “Jerry Pallotta” existed. The books follow such a uniform format, so carefully calibrated to the interest of little boys like Elliott, that I at first thought “Jerry Pallotta,” like “Franklin W. Dixon” of the Hardy Boys novels, must be a pseudonym, slapped on whatever overeducated wretch had been contracted to write the latest entry. But as Elliott and I read and reread the books, I started noticing little quirks, such as a consistent awe at the deadly majesty of the saltwater crocodile (“Salty,” as we loyal readers know him), and references to what sounded like an actual boyhood spent playing sports and exploring near the sea. So I Googled Jerry Pallotta, found his website, sent him an email, and got a call from him that day. His books are combative, but the man is not.

Pallotta is 72, a Boston native with a thrillingly legitimate accent who spent his summers on the water in Scituate, lobstering and clamming and hanging with whichever of his six siblings or 71 first cousins happened to be nearby, and, by his own admission, not reading anything at all. He played sports at his Catholic high school and got a Catholic college education in business, married young (and for life), started a family, and went into the insurance business. He probably would have continued on to a happy, affluent obscurity if he hadn’t one day been reading one of those A Is For … alphabet books to his kids and, in that particular moment of inspiration responsible for launching the career of so many artists, said to himself, I could do better than this.

Pallotta wrote, designed, published, and distributed his first book, The Ocean Alphabet Book, himself, recruiting one of those 71 cousins to illustrate it. (From the start, the author’s preoccupations were evident: B Is for Bluefish: “Their teeth are very, very sharp, so don’t ever put your fingers in their mouths.”) And then he really got to work. He had read that “Jay Leno would perform 300 nights a year, so why shouldn’t I treat my career the same way?” he told me. He started visiting schools, bringing books, talking to kids—and he came away with ideas for more alphabet books: Birds! Beetles! Skulls! Icky bugs! He thinks he’s spoken to at least 2 million schoolchildren over the past 30 years. As he learned at Georgetown, a good businessman has to know his market.

For some artists—the ones who have a shot at passing into greatness—another moment comes when they realize that they want to see something in the world that does not yet exist. When Pallotta, stuck at the Atlanta airport during a thunderstorm in 2009, opened his notebook to write down “Killer Whale vs. Orca,” then “Lion vs. Tiger,” then “Grizzly Bear vs. Polar Bear,” he was creating something for a little boy who loved sports and fishing and running around the beach—but hated reading.

“I don’t wanna pick on anybody,” that little boy said to me, some six decades later, “but if a teacher said, ‘Hey, I want you to read a book about Betsy Ross making the first flag,’ but then, on the next desk, there’s a book with a python swallowing an alligator, I mean, which one is the kid gonna go for, you know what I mean?”

Pallotta paused. Then he said, “I’m not making fun of Betsy Ross.”

From the beginning, it was to be a series, with the title Who Would Win? on each cover in a typeface that Pallotta had designed himself, based on the Everlast boxing-glove logo. The combatants would be posed beneath in profile, like Ali and Frazier at a weigh-in, glaring, claws—or paws, or fangs, or tusks—at the ready. When he brought the proposal to his publisher and mentor at Scholastic, Judy Newman, some of her colleagues were concerned. The company sells most of its books through school book fairs, run by teachers. Would they want their charges, unruly as they already were, reading about conflict? Would the kids act out the fights? Goodness, would there be betting?

Newman told me, “My editorial director said, ‘Teachers aren’t going to like fighting.’ And I said, ‘I trust Jerry.’”

The first books sold well in the book fairs, but poorly in bookstores, until Newman thought to bundle five or six books into omnibus editions—Ultimate Showdown; Extreme Animal Rumble—and they started flying off the shelves. Pallotta added more battles—Green Ants vs. Army Ants, Walrus vs. Elephant Seal. Many were inspired by suggestions from his avid young readers (“I’ve had kids write to me with 80 matches they want—that’s 160 different animals—and they write on the bottom, ‘Please do these this week and get them to me.’”) or by visits to the Harvard Museum of Natural History.

He can see almost any animal he likes there, he told me, “except a panda.” Stuffed pandas are vanishingly rare, because China will let zoos take the animals for only a number of years before returning them. “It’s an interesting fact.” Which is why, I suppose, there is no Who Would Win? Giant Panda vs. Sloth. Yet.

Today, 21.7 million copies of Who Would Win? books are in print. That doesn’t include the countless homemade Who Would Win? books that schoolkids across the country create with crayons and computers and paint, because they, too, have something they want to see in the world.

Why are the books so popular? All animals eat, nest, and migrate, which is all well and good, but if an animal fights another animal, suddenly there are stakes, drama, suspense, and, occasionally, surprises. Pallotta let slip that in his first Who Would Win? book, he let the lion defeat the tiger, even though obviously a tiger would take down a lion. He wanted to provoke dissent.

As a young girl of my acquaintance once said to me, dismissively: “All boys are like, ‘Blah, blah, blah, violent stuff, violent stuff, blah, blah, blah.’” As per her insight, I had assumed that the books were popular mainly among boys. But girls have taken to them, too. The books, Pallotta told me, “are 99 percent facts,” with a fight at the end. Each animal is described as a character who has a home and habits and likes and dislikes, and some of the animals are—dare I say it—cute. All kids love stories and suspense, and if you think girls would shy away from battles to the death, may I introduce you to some KPop Demon Hunters?

“A little girl wrote to me,” Pallotta said, “asking me to do a Who Would Win? book with a bunny. And then she underlines, twice, Do not kill the bunny.”

Elliott will not want to read and reread his Who Would Win? books forever—at least, I hope not. But right now, he loves to wrestle and roughhouse. And he also knows an awful lot about pterosaurs. And sharks, and birds, and killer whales, and insects, and blue whales, and wolverines. The natural world, as Tennyson wrote, and as Pallotta demonstrated, is red in tooth and claw. That’s part of what makes it fascinating.