Emperors of the Deep: Sharks — The Ocean’s Most Mysterious, Most Misunderstood, and Most Important Guardians By William McKeever, HarperOne, 2019, 320 pgs. $25.99.

Since it’s 2019, you’ve already heard some of the facts and statistics that underlie conservationist William McKeever’s new book Emperors of the Deep, but even so, especially if you live near the ocean, those facts and statistics are worth repeating.

Sharks are responsible for a tiny handful of human deaths each year. You have a 1 in 265 million chance of being killed by a shark. You’re far more likely to die from rogue fireworks than by shark attack. Sharks are drastically over-hunted: humans killed 100 million of them in 2018 alone. As a result, many species of sharks are now being pushed to the edge of extinction. And since many species of sharks are apex predators, their extinction would have deep and long-term effects on the marine ecosystem — and therefore on humans.

In short, sharks face an enormous conservation crisis, and that crisis might have been addressed long ago if not for a book and a movie: in 1974 Peter Benchley’s Jaws told the story of a persistent, malevolent shark haunting a beachside community, and in 1975, Steven Spielberg’s movie adaptation cemented in the world’s imagination the idea of sharks as remorseless human-eating machines.

That idea has always been wrong, and in Emperors of the Deep, Mr. McKeever harpoons it again. Sharks hunt close to shore at sunrise and sunset, and since their preferred prey are seals, a great many of their attacks on humans are simply cases of mistaken identity. As McKeever points out, this can be seen even in the nature of those attacks. Sharks dash in, take a surprise bite, realize their mistake and move on.

“If sharks were to view humans as prey, we would expect to see certain shark behaviors, and human victims would show certain telltale marks,” Mr. McKeever points out. “We would see sharks taking multiple bites, as wolves do. We would also expect to see sharks feed completely on the person who had been attacked.”

Sharks don’t do that, because sharks have no interest in preying on humans. But as Emperors of the Deep makes appallingly clear, the feeling isn’t mutual. Shark fins sell for hundreds of dollars a pound in China and the Pacific Rim, shark meat is increasingly harvested from oceans that have been depleted of traditional fish stocks, shark byproducts are sold as everything from aphrodisiacs to tourist trinkets.

The shark extinction market has never been stronger.

Mr. McKeever’s goal, valorous and likely doomed, is nothing short of undoing the decades-long work of Jaws and re-adjusting the world’s attitude toward sharks. In the course of his book, he talks to fellow conservationists, marine biologists and specialists on the long paleobiology of sharks and their 450 million-year history on Earth.

He consults with Greg Skomal, senior fisheries biologist at the Massachusetts Division of Marine Fisheries and something of a Grand Old Man of shark-wisdom for the Cape and islands. He spends time with locals in shark hot-spots, and everywhere he finds fellow true believers, people who have seen a very different side of sharks from that portrayed in popular culture.

“A fear of sharks has led people to seek the thrill of catching them,” Mr. McKeever writes. “In sharks and in life, fear is often the absence of knowledge.”

Emperors of the Deep brims with such knowledge, and with a deeper spirituality that seems to animate Mr. McKeever in his mission. “The salt in the sea is the same salt in our blood,” he writes. “Nature is not something foreign but something that lives within us.”

Thanks to an explosion in seal populations in the last two decades, sharks have been congregating around the Cape and islands in greater numbers than sea-watchers have seen in decades. With more sharks come more reminders of rudimentary precautions: don’t swim at dawn or dusk, don’t swim alone, don’t swim near seals (or, for that matter, rotting whale carcasses — a thing some people have considered a lark); respect the fact that when you enter the ocean, you are a stranger in a world of wild animals.

William McKeever would like to add a mental note to all this common sense, since Emperors of the Deep seeks to change not only behaviors but mindframes: “When a shark’s dorsal fin breaks the surface, we should breathe a sigh of relief that the waters are healthy and will remain healthy as long as sharks are left alone to perform their role.”

There will be a book signing with William McKeever along with a screening of his documentary in progress at the Martha’s Vineyard Film Center on Wednesday, July 3 at 7:30 p.m. The Film Center is located at 79 Beach Road, Vineyard Haven.