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. Her book Home of the Brave has won several awards. She also wrote a chapter book series in 2008–09 called Roscoe Riley Rules.

Ivan was a western lowland gorilla born in 1962 in what is now the Democratic Republic of the Congo. He was captured from the wild as a baby and brought to live with humans. For the first few years of his life he lived with his owners, but he soon grew too big for a human house and they moved him to a 14' x 14' concrete enclosure on display to the public at the B&I shopping center in Tacoma, Washington, where he spent the next 27 years of his life.