His second business is a software start-up that Risan, using the shopworn promotional language of entrepreneurs everywhere, swears will “revolutionize” computer security. He says he is working with everyone from the Internal Revenue Service to the National Security Agency to put his software on government and corporate computers. In the start-up’s office, though, I see only a single employee working beneath whiteboards covered with calculations.

What one can say for certain is that, whatever the success of his business ventures, Risan is one of the country’s leading collectors of rare guitars. When he put nearly 300 of them up for auction two years ago, Guitar Aficionado termed it an “immaculate collection,” a “staggering” assemblage featuring instruments used by the likes of Eric Clapton, Mick Jagger, and Stephen Stills. Its centerpiece, still in Risan’s hands, is an 1835 Martin long owned by Mark Twain. In 1999 Risan played a Stephen Foster song on it on National Public Radio.

Dozens of guitars are on display at Risan’s home, a tidy urban compound packed to the rafters with modern art and collectibles, including a Warhol screenprint, and Risan’s latest obsession, antique British chess sets. We enter past a Jaguar in the carport, into a small room hung with graffiti-inspired paintings. “This is my Banksy room,” Risan says, taking a moment to explain the stories behind several of them.

Through the next door is a courtyard with a glassed-in guesthouse, a workshop where Risan’s assistant is busy restoring an antique guitar, a conversation pit, and a hot tub sitting under a set of bison horns.

We turn away from all this, stepping into the bungalow, then through a kitchen into a dining area.

“And in here,” Risan says with a flourish, “I might as well show it to you first. This is my Falcon.”

Suddenly here it is, plopped down in the middle of an antique chessboard like a massive rook, a foot-high black statuette of a falcon. The hunched, brooding shoulders are instantly recognizable.

There is a long moment of silence.

“This is the thing dreams are made of,” Risan announces.

I’m not sure what to say. He has told me he actually owns two Falcons. I ask where the other one is. “I leave it downstairs,” Risan replies. “It’s too fucking evil. It has the presence of surrealism. American surrealism. The evocation of evil that it manifests is not normally the kind of thing I like to collect. I like the Warhols, the chessboards. So I leave it in the basement.”

This is a lot to digest. Risan senses my skepticism.

“I know, right?” he says with a smile. “Weird. Weird guy with a lot of art.”

Flock Together

Over the last 25 years Risan has assembled an impressive team of allies, including a noted U.C.L.A. film professor and a former head of the United States Copyright Office, all of whom believe Risan’s Falcons are genuine. Risan puts the Falcon down on a tabletop in his courtyard and takes a seat beside it. “Ready?” he asks.

Risan describes himself as a mathematics prodigy who entered college at 16, eventually attending the University of California, Santa Cruz, Berkeley, and Cambridge University. In his late 20s, he says, he burned out and began a new life trading stocks and rare guitars. It was in 1985 or 1986 that he saw one of the Falcons for the first time, in the offices of a San Francisco illustrator who wanted to buy one of his guitars.

“I knew what it was immediately,” he remembers. “It was just sitting on a table.” The illustrator said he had two more identical Falcons, and they had all been used as props in the 1941 movie. They had been given to him by his son who, while working at Warner Bros. in the early 1980s, obtained them from a colleague who was in the property department. He thought they were genuine, but he had no way of knowing. Intrigued, Risan made two of the Falcons part of the guitar deal. (A few weeks later he got the third and then sold it.)