Feeling certain that they wouldn't find a publisher to back such a macabre project, Ghiglieri and co-author Tom Myers—a physician who'd spent ten years treating patients on the Canyon's South Rim—decided to pony up $45,000 in printing and production costs and release it themselves. They both tapped their savings, loaded up with books, and hit the road, distributing copies of Over the Edge: Death in Grand Canyon to bookstores, roadside cafés, and shopping malls in Arizona and Las Vegas.

"It was pretty humbling," recalls the 60-year-old Ghiglieri. "It felt like we were two 14-year-olds looking for our first bag-boy jobs at the grocery store."

The book swiftly found its audience, though, and by this spring Over the Edge was headed for its 17th printing, having sold more than 150,000 copies and become the bestselling item at the bookstores on the South Rim. It was the dark-horse publishing success story of the outdoor world, and this month Ghiglieri—who earned his Ph.D. studying chimpanzees in Uganda and is affectionately known to his fellow Canyon boatmen as "the Doctor"—will extend the brand to include a park that, like Grand Canyon, is a notorious death trap for unwary tourists and adventurers.

Off the Wall: Death in Yosemite, which Ghiglieri co-wrote with former National Park Service superintendent Charles "Butch" Farabee, is due out in late May. Like Over the Edge, Off the Wall is carefully organized according to the various ways one can bite the dust in the backcountry. In addition to rock falls, airplane accidents, and boating debacles, the books offer a rich smorgasbord of drownings, climbing errors, murders, tree falls, suicides, flash floods, BASE-jumping mistakes, and random disappearances.

The stories evoke grisly fascination, but they also serve up important don't-be-this-guy lessons that, Ghiglieri hopes, might reduce the number of tragic mishaps taking place inside the parks. We caught up with the Doctor this spring to talk about his research, and about how good things can come from studying very, very bad accidents.

OUTSIDE: Would it be fair to say you're completely obsessed with death?
GHIGLIERI: I'm not obsessed with death at all—in fact, I'm so unobsessed with death that I never want to do another book like Over the Edge or Off the Wall again. What I am kind of obsessed with is prevention, especially when so many of the accidents chronicled in both books are completely avoidable. It's fair to say I became obsessed with that.

That's really why you wrote them?
Yes. I've been a river guide for 34 years, and I was struck by the fact that people were getting killed and maimed in Grand Canyon and Yosemite every month of the year, yet back in the early days, nobody seemed to know or care about what, specifically, was going wrong. Records were kept, of course, but the files were often just thrown into a box somewhere and forgotten. So I thought it would be a good idea to gather and correlate this information and then look for patterns. In the process, I discovered it's actually kind of fun to learn about this stuff. Especially if, you know, you're not the one getting killed.

How did you get your hands on all this information?
The primary source was the Park Service's own Incident Reports, but frequently the old reports were incomplete or lost or had simply been thrown away. So we looked in the county sheriffs' reports, we read the complete microfilm records of every newspaper in northern Arizona and around Yosemite, we combed through all the history books, and we conducted extensive interviews. It was a pretty exhaustive process that, with each book, took about three years—a search for diamonds among the pebbles.