If you go to Davis, California, and try to pay a visit to Slade Fiero, it's quite possible that you will drive right past his house. Because of his peculiar line of work, one that gives him a unique vantage point on the wormy root cellar of the male psyche, you might expect to find him somewhere dank and drippy and catacombed. A place, maybe, like that tumbledown Victorian in Fight Club. But what you'll find instead, under a cloudless blue Sacramento Valley sky, is a well-tended suburban house. There's an orange tree basking in the sunshine and a wrought-iron fence around the lawn. There are tinkling wind chimes and cacti in terra-cotta pots. Elementary-school kids float down the street in a bicycle squadron just as Fiero opens the front door.

It's all very Blue Velvet, an impression that only increases when Fiero appears. He is shirtless, his torso wrapped in tattoos, and he makes his way down the front path with a motion that might be described as a sidewinder's wobble.

When he shakes hands and says, "Please take your shoes off before you hit the carpet," there is something about the whispery precision of his enunciation, the popping intensity of his gray-blue eyes, and his blend of gentility and menace that reminds you right away of Dean Stockwell's character in David Lynch's 1986 masterpiece.

Blue Velvet is all about how you never really know what's going on next door, and the same could be said of Slade Fiero's own façade of domesticity. Even though Fiero is a world-renowned specialist, a lot of his neighbors have no idea what he does. In fact, so rare is the nature of his expertise that he may qualify as the ultimate specialist.

For almost a decade Fiero, who is 48 years old, has made a comfortable living as the RealDoll Doctor. Which means that if you happen to own a state-of-the-art sex doll, and your doll has, in the course of your amorous pas de deux, somehow managed to snap, tear, sag, go all blotchy, or dislocate a knee, Fiero is the man you call to repair it. Think of Geek Squad. Now think of synthetic nipples.

Since 1996, the year that a young entrepreneur named Matt McMullen launched Abyss Creations, the Southern California company has manufactured about 4,000 RealDolls, shipping them around the world. "The original concept I had was actually not a sex toy at all," says McMullen, who is 39 and has a background in sculpture and drawing. "It was intended to be a poseable mannequin, or simply a form of art." He quickly noticed that a lot of people saw the dolls in an erotic way. The company makes about 300 RealDolls each year. A standard-issue model sells for $6,500, while a meticulously customized one can go for as much as $50,000. Painstakingly sculpted in silicone and hand-painted to feel and look like real women—or at least real centerfold models—the dolls have become a cultural phenomenon. They're a perennial source of amusement on Howard Stern's radio show. They've made appearances on Nip/Tuck and Boston Legal. Art exhibits have featured haunting photographs of the dolls and their tender paramours, and in 2007 Ryan Gosling starred in Lars and the Real Girl, an Oscar-nominated portrait of one lonely man's love for his silent and synthetic companion.