It was a dark and stormy night.... Also a really lucrative one for author R.L. Stine, whose Goosebumps and Fear Street series have become a national training ground for Stephen King readers. Never heard of Stine? Maybe that's because you're old enough to drive. But the Nickelodeon generation propelled his 96th book, The Headless Ghost, to the No. 1 bestseller slot this fall, above Michael Crichton's The Lost World and Colin Powell's My American Journey. "It's thrilling in a way, and totally surprising," says Stine, 52, who maintains an unassuming Manhattan lifestyle with his wife, Jane, 49, a book editor, and their 15-year-old son Matthew. "Nobody is more amazed than me." Certainly not his publisher, Jean Feiwel of Scholastic, who credits Stine's hair-raising success to his "very good ear for kids." In his stories, "I have no crying, no hugging, and the kids never learn anything about themselves," Stine says proudly. On the contrary, it is his age-appropriate chills (nobody dies in Goosebumps, geared to grade-schoolers; heads roll in Fear Street, for adolescents) that have enthralled readers since 1989. Goosebumps is now a weekly Fox TV series, and two movie deals are in the works. The author even has his share of famous fans, including Steven Spielberg, who reads Stine to his own young brood. Still, "I'm always thinking, 'Am I going too far?' " Stine says. " 'Should I do something funny so it's not too scary?' " Better not mess with success. In October, Stine's first adult novel, Superstitious, was published to a critical thud. But the author, who commanded $1 million for Superstitious screen rights, remains unbowed. "I might sell 30 million books this year, and no one else comes close. Of course," he adds, "no one else writes 24 a year."