Hiking through the Nevada desert in 1968, "20 miles east of Vegas but light years from neon," Colin Fletcher came upon an antique wooden trunk. Behind it, in and around a small cave, were littered the remains of a turn-of-the-century camp evidently occupied by a lone person, abandoned long since and subsequently vandalized. In the fading autumn afternoon, with his water supply dwindling, Fletcher had time only for a brief examination of his find.

There was little to look at: a rusty sheepherder's stove, frying pan, coffeepot and Dutch oven, a shovel, a bucket, a pair of small, tattered shoes, a jumble of cut firewood -- all coated thickly with dust. Even the trunk itself, weathered and mysterious against a desert cliff, proved to be empty except for two ordinary brown paper bags. Fletcher paused and wondered, but time and thrist allowed no more than a cursory inspection.

Such finds are odd and startling, but hardly unusual. A clump of daffodils on a wild hill, an ax blade or wagon shaft buried in forest mulch, a shard of china doll among the roots of a fallen tree, all are abrupt reminders that others have shared our claim upon a wild piece of earth. The moment passes, and we move on.

Fletcher, too, moved on, back to the civilized pursuits that claim us all. But a year later he went back to the cave, prompted by no more, he thought, than idle curiosity and the prospect of a pleasant 10-day interlude in the desert. He would realize much later that more than vague wonder and curiosity compelled him to return. Something in the trunk and other dusty artifacts scattered there under the desert sky touched him more deeply then he knew.

After 10 days in his mysterious "Trunkman's" cave, sifting through his belongings, surrounded by the sky and rock and wild creatures that Trunkman, too, had known, Fletcher left knowing a good deal about the personality of the stranger who had chosen the camp for his own desert interlude. But what he had found only muliplied the unknown. Who was Trunkman? What was his name? When and why had he lived here? For how long, and why had he left?

Fletcher wrote an article about his find, offering $100 for further information about Trunkman. An elderly woman, Grace Mazeris, responded to the article, claiming to have known and once lived with Trunkman, whom she had called Bill Simmons, or Chuckawallah Bill. Simmons was a disabled veteran of the Spanish-American War who spent his days wandering the desert, filing mining claims that he never returned to develop. Grace had met him at the Salton Sea in 1932, when Bill was 67 and she was 40. For once a year, they traveled the California desert and mountains together, prospecting and lived for a time in a rock house near Garnet. She had never seen the cave in Nevada, but Bill had often spoken of it, and his descriptions fit the cave of Fletcher's Trunkman.

Almost idly, Fletcher pursued the leads Grace provided, hoping to track Bill Simmons to Trunkman's cave. His easygoing, conversational narrative traces Simmons through his Army records and numerous mining claims filed under a variety of aliases in the Southwest. Fletcher's pleasant yarn of discovery changes abruptly, however, with the death of Grace Mazeris shortly after one of her conversations with him. A "natural statute of limitations" imposed itself on the search for Trunkman: The few people surviving who may have known him were dying out. After Grace's death, Fletcher dedicated himself to his task in earnest.

The tracks were faint indeed. For 10 years Fletcher followed them from the National Archives in Washington to Braddock, Pa., where Simmons was born and a few elderly relatives still remembered him as the uncle who went West and never came back. Following the trail west, Fletcher reconstructed Simmon's life. With the same understanding that had first drawn him back to the cave, he gathered the pieces from the survivors who remembered with affection and respect the solitary wanderer who had drifted in and out of their lives.

Fletcher never did find indisputable proof that Bill Simmons was Trunkman or had ever occupied that Nevada cave. But 10 years of tracking unearthed no evidence that Trunkman and Simmons could not have been the same person, and the personality of the Simmons that Fletcher pursued so doggedly is never at variance with the character he glimpsed in the relics of the desert cave.

Whether or not Simmons and Trunkman were the same person matters little in the end. The cave in the desert that held so powerful a fascination for Fletcher introduced him to Simmons, transforming an idle mystery into a touching biography of a man whose greatest gift to earth was the little harm he caused it. Whatever civilized din or grief Bill Simmons fled, he found sanctuary in the cave or some comparable retreat, a turning point in his life that set him on a course he would follow for 40 years.

In this tale of "an ordinary man who was fear from ordinary," Colin Fletcher has written a far from ordinary book. To aculture obsessed with youth and achievement, "The Man From the Cave" brings affirmation of age, memory and the benign defiance of a man true to his own wavering star. "In its way, the second half of his life he had been a work of art, a triumph," Fletcher concludes. "The Man From the Cave" is equally a work of art, a triumph, a monument to the unique spark of humanity Fletcher intuitively recognized in a wild desert cave.