This month, I’ve been thinking about the joys of interactive books, those books that welcome readers in and treat them as active participants in the world of the story. Some kinds of books are obviously interactive, like choose-your-own-adventure-style novels and lift-the-flap board books. Other books can be more subtly welcoming in their design or content, allowing characters to address the reader directly, or giving readers a mystery or puzzle to solve. And readers themselves have the power to interact more deeply with any book they love. When I speak at elementary schools, students love to tell me about how they’re writing fanfiction, turning the plots of adventure novels into recess games, or pursuing other projects inspired by their favorite stories.…