MARY POPE OSBORNE and NATALIE POPE BOYCE are sisters who grew up on army posts all over the world. Mary is the author of over 50 acclaimed books for children. Natalie has worked as a children's librarian and as a teacher of English and ESL. SAL MURDOCCA has been illustrating and writing books for children for many years. He has illustrated every book in the Magic Tree House fiction series and the Magic Tree House Fact Tracker nonfiction companions.