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 E.S.L. This is their fourth book together. The authors live in Goshen, CT, and West Stockbridge, MA, respectively. 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 Research Guide nonfiction companions. Sal and his wife Nancy are avid runners and have toured Europe on bicycles. He lives in Rockland County, NY.Osborne, Mary Pope is the author of 'Sabertooth Tigers and the Ice Age A Nonfiction Companion to Sunset of the Sabertooth', published 2005 under ISBN 9780375823800 and ISBN 0375823808.