How will the books on this list challenge you? Some cover difficult topics that will have you reexamining your own feelings about various issues. Others deal with complicated moral issues. Some of these books will have you itching to share with your friends so you can discuss what it all means. Warning: the books on this list might even leave you with a serious book hangover for days. So consume with caution. Remember that summer reading list your English teacher would give you before you left for break every year? Think of this as the adult version of that list. Here are your 2021 must-read books (both fiction and nonfiction) to keep the brain wheels turning this summer.