(FORTUNE Small Business) – BOB CHILDS, 51 Cambridge, Mass.

FORMER LIFE: Solitary maker of world-class violins CURRENT PURSUIT: Keeping his violin business going while building a paychotherapy practice

"When are you coming back?" Bob Childs heard the question, but he didn't understand it, not right away. He was just 24 years old, living alone in a cabin in the woods near Amherst, Maine, working in a furniture factory and playing fiddle (he later joined a band called the Moosetones). His violin had developed a crack in the seam (probably because it was so cold in the cabin), and he had brought it to Ivie Mann, a local luthier, for repairs. Mann was past 70. He had lived in Maine all his life. The first time Mann shook hands with Childs, he had held on for what seemed like 15 minutes, like destiny's own grip, while he took the young man's measure. Now Mann was pointing at the pile of wood on his work bench and asking again, "When are you coming back?" Suddenly Childs understood. "Oh, you're going to teach me?"

Childs apprenticed under Mann for two years and later trained with master violin makers on both coasts. Now 51, he ranks among the elite practitioners of his craft. Working alone in a sunny, third-floor workshop in North Cambridge, Mass., he builds violins and violas for a range of top players, including a member of the Boston Symphony orchestra, an all-Ireland fiddle champion, and a Scottish national champ. Every instrument Childs makes shares what he calls a "familial quality," yet no two sound exactly alike. He prides himself on taking time to discern the particular sound each client hears in his or her mind's ear--for some it's a "bright soprano," for others something "darker, more mysterious"--then duplicating it. He builds five, maybe six instruments a year and works only on commission. Twelve years ago you could have had a Bob Childs violin for $3,000. These days you'll pay $14,000, and the waiting list is a year long.

One reason for the backlog is that Childs is in his workshop only 30 hours a week. On Tuesdays and Thursdays he unties his apron, changes out of his jeans, and descends a flight of stairs to a book-lined study--the office of Dr. Robert M. Childs, clinical psychologist. While Childs has been making violins since his 20s, it wasn't until he was well into his 40s that he became a practicing therapist, specializing in patients who are artists. It came down to a choice about how he wanted to live, he says, especially as he got older. The deeper he was drawn into what he calls the "mystery of what makes an instrument sound good," the more isolated he felt, planing and sanding at his bench, alone for days on end. For Childs, concentration required solitude; there was no way around it, and "That really bothered me," he says. "I wanted to figure out something I could do that involved working with other people."

Between making violins and seeing patients, Childs earns about $130,000. He has never married, has no kids, lives simply, and could easily get by on either income alone. While running two small businesses at once may sound stressful, Childs, like many entrepreneurs, has a hard time thinking about the work he does as work. It's life, his life--as unique, as versatile, and as carefully assembled as a Bob Childs violin, and designed to last far beyond an age when most Americans retire.

Childs says today that for him, making violins is "second nature," but that's only because he's worked so hard at it for so long. Early in his apprenticeship, he was given a block of wood and a small plane and told by his teacher to make a perfect square. It had to be flat enough to create suction when placed on a piece of granite, says Childs, who took a week to complete the task. "I had no concept of what that was about." A couple of years later the same teacher knocked on the door of Childs's trailer (a step up from a cabin, presumably) in Sisters, Ore., with a bottle of wine, and announced, grinning, "We're going to burn one of your violins!" The lesson of the day: You're making progress but you're not there yet. "It was a shock," says Childs. "But he was my teacher and I wanted to learn, so I did what he said."

In the mid-1980s, after ten years of dedicated study, Childs almost gave up. Handicapped since childhood by poor vision, he had begun to despair of ever being able to meet his own exacting standards of craftsmanship. He had a falling-out with his teacher at a prestigious violin shop in Philadelphia, after which he quit (or maybe he was fired), enrolled in art school, entered therapy, and began exploring issues in his past that until then he'd tried to ignore.

Childs was given up for adoption at birth. Ultimately he was raised by loving parents, but he spent the first 2 1/2 years of his life shuttling between foster homes. He learned the identity of his birth mother only after she had died; she took the mystery of who his father was to her grave. While he was in therapy, Childs dreamed one night that his search for his birth parents had brought him to the border of a "neutral country." The border guard wouldn't let him pass but led him into the guardhouse and down a long corridor to a windowless room. In the middle of the room was a light shining on a table. On the table was a violin. Engraved in the wood of the violin was the image of a small boy, crying. To Childs, the meaning of the dream is clear: Making violins is his way of giving form to the pain he experienced as a child, a pain that "doesn't have words."

In 1988, Childs moved to Cambridge and opened his own shop. He enrolled in a master's program at Harvard and later transferred to the Massachusetts School of Professional Psychology, where, after eight years of part-time study, he graduated with a doctor of psychology degree in 1998. As his practice has grown, so has his reputation as a violin maker. He estimates that he's sold about 125 violins by now, to musicians all over the world. Together they make a community, and once a year, around Christmas, members of that community come together for a concert series. A whole stage full of fiddlers--Childsplay is the name of the group--with Bob Childs, beaming, in the middle.

"Not all violin makers will agree, but I believe that the soul of the maker goes into the instrument," he says. "You want whatever it is you're expressing to live beyond your own life. When I have everybody gathered around me, it helps me feel that."