Margaret Peterson Haddix was born in Washington Court House, Ohio and grew up on a farm near there. She graduated from Miami University in Oxford, Ohio, with degrees in English/journalism, English/creative writing, and history. Before her first book was published, she worked as a newspaper copyeditor in Fort Wayne, Indiana; a newspaper reporter in Indianapolis; and a community college instructor and freelance writer in Danville, Illinois.
Haddix has written more than 30 books for children and teenagers, including Running Out of Time; Don't You Dare Read This, Mrs. Dunphrey; Leaving Fishers; Just Ella; Turnabout; Takeoffs and Landings; The Girl with 500 Middle Names; Because of Anya; Escape from Memory; Say What?; The House on the Gulf; Double Identity; Dexter the Tough; Uprising; Palace of Mirrors; Claim to Fame; The Always War; Game Changer; the Shadow Children series; and the Missing series. She also wrote Into the Gauntlet, book 10 in the 39 Clues series. Her books have made New York Times Best Seller lists and American Library Association (ALA) annual book lists, and they have won the International Reading Association's Children's Book Award and more than a dozen state reader's choice awards.