Occasionally, people will come into Betty-Carol Sellen’s bed-and-breakfast south of Annapolis and ask whether she’s the one who made all of the artwork around the house. Sellen’s reaction is usually mystified, because the artwork is a diverse collection of out-of-the-mainstream art. “There’s no way one person could do so many different styles,” she says.

Sellen and her collaborator, Library of Congress Assistant Division Chief Cynthia J. Johanson, recently published Self-Taught, Outsider, and Folk Art: A Guide to American Artists, Locations, and Resources (McFarland). Within 326 pages of fine print, Sellen and Johanson provide lists of galleries, museums, festivals, exhibitions, and organizations that work with nonmainstream art. Most important, the authors provide thumbnail biographies of several hundred artists across the country. A few are well-known, such as Grandma Moses, but most of the rest are obscure and fit somewhere on the scale between eccentric and insane. Needless to say, these mini-biographies are wholly unlike those of most art-history textbooks, written as they are with a bracing mix of wonder and wackiness.

Remarkably, Sellen estimates that, since becoming a collector and chronicler of the subject more than 15 years ago, she’s met 80 percent of the artists in the book. When Sellen began to research the first edition (which had a different publisher and a slightly different title), she found no way to do so other than by hitting the pavement. “At first, no one knew me,” she says. “It was like a lot of fields—it was cliquish, and there were old-boy networks. I traveled all over to talk to gallery owners because they would not answer my questions over the phone. When I did that, I got to meet a lot of the artists.”

Before she retired to Deale, Md., Sellen worked as a librarian at the University of Washington and at Brooklyn College. She first learned about outsider art in the early ’80s while on sabbatical in New Orleans. Failing to find a good reference work on the subject, she decided to create one.

The field she writes about is sui generis—a debate still rages over how to label it. Some favor “visionary art”; others prefer “primitive art” or “naive art.” Sellen hedges her bets by using three different descriptors in her book’s title. (She says “self-taught” is actually her favorite.) Some of the artists she’s come to know have had religious visions; others have come to art after being forced into disability following serious injuries while doing blue-collar work. “People generally don’t see the difference between childish and childlike,” Sellen says. “They say, ‘My kid could do that.’ My best response is ‘Show me.’ Because they can’t.”— Louis Jacobson