Mary Pope Osborne is the author of the New York Times number one bestselling Magic Tree House series as well as co-author of the Magic Tree House Fact Tracker series, along with her husband, Will, and her sister, Natalie Pope Boyce. For more information, visit the Magic Tree House® website at MagicTreeHouse.com! 

Natalie Pope Boyce and Mary Pope Osborne 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. Natalie makes her home 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. For more information, visit the Magic Tree House® website at MagicTreeHouse.com! 

Sal Murdocca has illustrated more than 200 children's trade and textbooks. He is also a librettist for children's opera, a video artist, an avid runner, hiker, bicyclist, and a teacher of children's illustration at the Parsons School of Design. Sal lives and works in New York with his wife, Nancy.