Margaret Peterson Haddix

Margaret Peterson Haddix is an American writer, born in 1964, best known for two children's series: Shadow Children, which ran from 1998 to 2006, and The Missing, which ran from 2008 to 2015. Her other titles include Double Identity, Just Ella, and Running Out of Time. She also wrote the tenth volume of the multiple-author series The 39 Clues, Into the Gauntlet.