The New York Times best-selling author goes on a rollicking journey to understand the enduring power of puzzles: why we love them, what they do to our brains, and how they can improve our world. What makes puzzles—jigsaws, mazes, riddles, sudokus—so satisfying? Be it the formation of new cerebral pathways, their close link to insight and humor, or their community-building properties, they’re among the fundamental elements that make us human. Convinced that puzzles have made him a better person, A.J. Jacobs—four-time New York Times best-selling author, master of immersion journalism, and nightly crossworder—set out to determine their myriad benefits. And maybe, in the process, solve the puzzle of our very existence. Well, almost.