There’s nothing quite like the dorsal fin of a great white shark to instill fear and highlight the timeless conflict between humans and nature. TV ratings during any given “Shark Week!” and museum attendance during shark exhibits suggest humans have a primordial fascination with the majestic and carnivorous invertebrates.

Toronto-born magazine editor Susan Casey was captivated by a BBC documentary about white sharks and the Farallon Islands, an inhospitable Pacific Ocean outpost less than 30 miles west of San Francisco’s Golden Gate Bridge, and decided to go there. The book is her recounting of several trips and adventures there with Peter Pyle and Scot Anderson, the two leathery principals of the Shark Project, a rough-and-tumble crew that lives on the Farallones.

The obsession in the title refers mostly to Casey’s desire to challenge herself and escape the consumerist culture of which she is an obvious disciple. She feels liberated on the desolate, wind-lashed, fog-bound rocky outcropping while covered in bird guano. Even after not showering for a week, she writes, “I always felt sexier than I’d ever felt walking around Manhattan all cleaned up and wearing Gucci heels or La Perla underpants.”

In between earnest mocking of what is essentially her own social class of “spoiled, soft-palmed candyasses with misplaced superiority complexes,” Casey retells a fascinating story of a place that was, 150 years ago, rich with bird-egg prospectors who were every bit as determined as the California gold prospectors of the same era. The seal population in the Farallones means sharks galore, but the violent, unpredictable weather, harsh and treacherous landscape, and lack of amenities keep most humans from the islands. Casey captures well the stealth and terrible beauty of the sharks and their distinctive personalities, as well as the isolation, frayed nerves, teamwork, and mild paranoia of the human players in this drama.

There is no doubt that the book brings attention to the important projects dedicated to learning more about great white sharks, but one can’t help getting the niggling feeling that part of Casey’s encounter with the Farallones was like bungee jumping or heli-gliding writ large, just another form of elitist thrill-seeking that none of her Manhattanite acquaintances will be able to match at the next cocktail party.