BOOKS

By JANICE C. SIMPSON

The Bobbsey Twins and Nancy Drew were too boring. And Trixie Belden? She was just plain dorky. But then Rebecca Langlois, a Dallas sixth-grader, discovered Kristy, Claudia, Mary Anne and Stacey. As just about every girl between eight and 12 knows, those are the founding members of the Baby-Sitters Club and the hottest fictional characters with today's preadolescent literary set. "They're funny and exciting, and the adventures they go through are stuff that can happen in real life," says Langlois, 12. She heads for the bookstore the minute the latest installment arrives.

That kind of devotion has sold more than 41 million copies of Baby-Sitters books since the series, which now runs to 40 volumes, began in August 1986. About 6 million copies of a companion series, Baby-Sitters Little Sister, for slightly younger readers, have been snatched up in just two years. Now the spin-offs are descending. Baby-Sitters calendars and school planners are already on the market, as are two videos. Milton Bradley sells a Baby-Sitters board game, and Remco Toys plans a new line of Baby-Sitters dolls, complete with a closetful of outfits and tiny tots to tend.

Baby-Sitters was the brainchild of Jean Feiwell, editor in chief at Scholastic Inc., which publishes juvenile books. She noticed that tales with the word baby-sitter in the title sold well to young girls eager for that first taste of grownup responsibility. The club members -- now totaling seven -- and their experiences in fictional Stoneybrook, Conn., were created by Ann M. Martin, a former schoolteacher and children's book editor. Scribbling on yellow pads from 8 a.m. to 6 p.m. daily, the 36-year-old author, who lives in Manhattan with her cats Mouse and Rosie, turns out a 150-page Baby-Sitter book and a 100-page Little Sister volume almost every month.

Librarians give the books mixed reviews. Some find the plots predictable and the prose pedestrian, but others praise the series for attracting children who aren't always comfortable with books. "The reading level is pretty simple, and that's very important in my library, where English is a second language," says Janet Campano, who works at the Chinatown branch of the New York Public ; Library.

But Martin's main strength is her ability to tap into the ways young girls think and feel about life. Her stories explore the spectrum of preteen challenges from sibling rivalry and peer pressure to the death of a grandparent and the arrival of a new stepparent. Divorce is a fairly constant theme. "That's on the minds of kids a lot," Martin says. The books also touch on issues of race and ethnicity. Baby-Sitter Claudia, for example, is Asian and a talented artist, but she has trouble academically. "We wanted to defy the stereotype that every Asian is brilliant," says Feiwell.

There are still taboo subjects, however: Martin has avoided writing about drugs, sex and child abuse. "I think these topics are a little heavy for younger readers," she explains. Some kids like it that way. Such topics "would ruin the books," says Kathy Ames, 14, a Wyckoff, N.J., ninth- grader and a devoted fan. But others aren't so sure. "If these girls were real, they'd probably already be offered drugs and have to deal with it," says Langlois. Sounds like a new assignment for the Baby-Sitters.