Katherine Alice Applegate, known professionally as K. A. Applegate, is an American young adult and children's fiction writer, best known as the author of the Animorphs, Remnants, and Everworld book series. She won the 2013 Newbery Medal for her 2012 children's novel The One and Only Ivan. Applegate's most popular books are science fiction, fantasy, and adventure novels. She won the Best New Children's Book Series Award in 1997 in Publishers Weekly.