But the couple's wider influence stemmed from their four books, required reading for anyone interested in the past and future of the Eastern wilderness—or "wildness," as they often preferred to call it. Their seminal Backwoods Ethics, first published in 1979, was a practical guide to low-impact hiking and camping, while Wilderness Ethics, published in 1993, took a more philosophical tack, arguing for the preservation of an intangible "spirit of wilderness" threatened by an onslaught of cell phones, helicopters, and burgeoning numbers of winter campers. In the intervening years, the Watermans produced two exhaustive historical works on New England hiking and climbing from colonial days forward.

They were known as "the conscience of the Northeast mountains." But the closest friends of Guy and Laura's—you rarely heard one name without the other—thought their greatest achievement was the bond between them. "If you think of all the time they spent by themselves, it's remarkable," says Doug Mayer, a Web-site producer for the NPR program Car Talk and trails chairman for the Randolph Mountain Club in New Hampshire's northern Presidentials. "They were always so courteous with each other, paying attention when the other spoke, really loving and respectful."

As the news of Guy's death spread across the Upper Valley last winter, there was no shortage of speculation as to why he had walked out that door. "He had terminal cancer," the manager of a ski shop told me. "He couldn't stand the pain anymore." A hiker I met in the parking lot at Franconia Notch shrugged and said, "He was just an old Eskimo who went out on an ice floe." Some acquaintances referred to "personal demons," while many assumed he was simply despondent over the steady erosion of the wilderness he'd fought so long to protect.

There was, perhaps, a grain of truth in all these guesses, but few of these friends and strangers could have had an inkling of the disillusionment and pain that Waterman carried with him to the top of Mount Lafayette, including an enduring grief over two earlier family tragedies that would eerily prefigure his own death. Nor could anyone have predicted the anger and confusion that swirled in the wake of his suicide, or the heated controversy that developed over the ethics and cost of retrieving his body. The whole episode left many of the Watermans' followers questioning what was perhaps the community's central article of faith: the redemptive power of the wilderness. In the end, Guy Waterman was a man who turned his back on society and sought out the solace of the mountains, only to find that the mountains ultimately offered no guarantee of peace.