Gregor the Overlander is a children's epic fantasy novel. The book was written by Suzanne Collins and was published in 2003 as the first book of The Underland Chronicles. It was received well by critics, and was listed as one of New York Public Library's 100 Books for Reading and Sharing. It was featured by National Public Radio in 2005. Scholastic has rated the book's "grade level equivalent" as 4.9 and the book's lexile score as 630L, making it reading-level-appropriate for the average fourth or fifth grader.The novel has been published in several languages and is available as both an audiobook and ebook. Its United Kingdom edition was published under the alternate title Gregor and the Rats of the Underland.