MARGARET BLACKSTONE writes books about science as well as picture books. She lives in New York City. ELISSA HADEN GUEST is the author of the Iris and Walter easy reader series. She lives in San Francisco, California. BARBARA POLLAK has illustrated several children's books, including her own "Our Community Garden." She lives in San Francisco, California. While working on "Girl Stuff," the authors consulted a gynecologist, two psychologists, a sex educator, a dermatologist, and a pediatric nurse.