Could there be a civilization on a mote of dust? How much of your fate have you made? Who cleans the universe? Through more than fifty Koans -- pleasingly paradoxical vignettes following the ancient Zen tradition -- leading physicist Anthony Aguirre takes the reader across the world from Japan to Italy, and through ideas spanning the age, breadth and depth of the Universe. Using these beguiling Koans and a flair for explaining complex science, Aguirre covers cosmic questions that scientific giants from Aristotle to Galileo to Heisenberg have grappled with, from the meaning of quantum theory and the nature of time to the origin of multiple universes. Playful and enlightening, Cosmological Koans explores the strange hinterland between the deep structure of the physical world and our personal experience of it, giving us what Einstein himself called "the most beautiful and deepest experience" anyone can have: a sense of the mysterious.