Jean E. Karl, 72, who edited books for children and created Atheneum's Books for Young Readers division. Karl established the children's imprint in 1961 and headed it until her retirement in 1985, but had continued editing books until a short time ago. She also wrote a wide range of children's books--nonfiction, fiction and science fiction--under her own name or the name of her grandmother, R.W. Munson. Her books won eight Edgar Awards for mysteries, and books she edited garnered numerous Caldecott Medals, Newbery Medals and National Book Awards for her authors. Also the founder of Aladdin Paperbacks, Karl grew up in Chicago, attended Mount Union College in Alliance, Ohio, and began her career with a Chicago publisher. In 1956, she moved to New York as children's book editor for the Methodist Church's Abingdon Press. Alfred Knopf Jr. personally recruited her to start the children's department for Atheneum, which is now a part of Simon & Schuster. In an often-told anecdote about Karl, an Atheneum executive once called her the "juvenile editor," prompting her to call him the "senile editor" and remind him that "good children's books are never juvenile." On Thursday in Lancaster, Pa.