Answer
Yes, Suzanne Collins has not written any standalone novels to date. All of her published works have been part of a series. Her most famous series, "The Hunger Games," encompasses three books: "The Hunger Games" (2008), "Catching Fire" (2009), and "Mockingjay" (2010). She has also written "The Underland Chronicles," comprising five books from 2003 to 2007,