Sally M. Walker majored in geology and is the author of Sibert Medal winner
Secrets of a Civil War Submarine as well as many other nonfiction books, including
Boundaries: How the Mason-Dixon Line Settled a Family Feud and Divided a Nation and
Winnie: The True Story of the Bear Who Inspired Winnie-the-Pooh. Sally M. Walker lives in Illinois.
William Grill is the author-illustrator of
Shackleton's Journey, a
New York Times Best Illustrated Children's Book of the Year and winner of a Kate Greenaway Medal, and
The Wolves of Currumpaw. He lives in England.