The Andalite Chronicles is a science-fiction novel, and is the first companion book to the Animorphs series, written by K. A. Applegate. Within the timeline of the series, this book takes place before the first book in the series, The Invasion. The book was published in November 1997, and was followed the next year by the second companion book in the Chronicles series, The Hork-Bajir Chronicles. Before its wide release, however, the story was offered in the form of 3 separate volumes to school book clubs, which some considered a "typically savvy" marketing move.