The eagerly-awaited Hunger Games: Mockingjay Part 2, released in late November, quickly tallied nine figures at the American box office and an attendant sales boost for the Suzanne Collins adventure on which it’s based. Indeed, most of 2015’s biggest adaptations led to a paperback sales spike. The exception? Insurgent, which did decent box office (a $54 million US opening weekend) but whose book sales actually fell the week after the movie came out.