A recent high-altitude crime wave has left Sierra Nevada historians scrambling for clues. Nineteen summit registers—those ubiquitous books and papers that hikers sign on mountaintops—have gone missing since 2003. No one knows for sure who's taking them, but local climbers surmise that vandals or private collectors may be the culprits.

From the Rockies to the Appalachians, trail and summit logs have recorded the passage of boots through the hills since at least 1870. Yellowing pages rolled up and shoved into film canisters, brass tubes, or old glass jars—the registers sometimes look more like litter than historical records. But in the Sierra, the logs often boast signatures of bonafide wilderness legends—men like photographer Ansel Adams and environmentalist David Brower.

"This year I was on a peak with a register that's 50 years old. Only six people have been on that mountain in 50 years," says Belmont, California, native Steve Eckert, who has climbed all 247 of the peaks designated as notable by the Los Angeles chapter of the Sierra Club.

Not surprisingly, many Sierra climbers agree that the old registers should be safeguarded before they disappear into a souvenir hunter's collection, or the Sierra winds, forever. John Blaubach recovered a notebook from the summit of Mount Hilgard in 2002 and donated it to the Bancroft Library at the University of California at Berkeley, which maintains a collection of historic Sierra registers. "It was becoming a loose bundle of papers," he says. "I thought, 'This thing is supposed to be historical, but it's soon going to be history.' "

Cagey Sierra buffs suggest that deep within the range there could be a peak with a register so ancient it bears the signature of the father of Sierra mountaineering, John Muir. Where might it be? "Well," says Robin Ingraham Jr., a wilderness landscape photographer and leader in the movement to preserve registers, "it's not that I don't trust you. I'm just not telling."

From the print edition, February 2005