MARY POPE OSBORNE and NATALIE POPE BOYCE are sisters who grew up on army posts all over the world. They work together on Magic Tree House Fact Tracker books to give readers information about the places, time periods, and animals that Jack and Annie discover in their Magic Tree House adventures. Mary lives in northwest Connecticut. Natalie makes her home nearby in the Berkshire Hills of Massachusetts. Mary is the author of all the Magic Tree House fiction titles, as well as many more books for kids.