4. The Outsider by Stephen King
Legendary horror author Stephen King delivered two books in 2018, but it was the eerie May release The Outsider, not the more critically acclaimed fall release Elevation, that moved the most copies in 2018. Perhaps it’s The Outsider‘s dark, creepy subject matter, which drew parallels from critics to King’s earlier work It. Perhaps it’s the book’s earlier publication date, which allowed the title more time to accrue sales. Or perhaps it’s simply the fact that The Outsider is already in production to become an HBO miniseries starring Rogue One actor Ben Mendelsohn. Either way, given the pending series, The Outsider is destined to remain on the best-seller lists for the foreseeable future.