UCLA neuroscientist Dean Buonomano investigates the relationship between the brain and time: What is time? Why does time seem to speed up or slow down? Is our sense that time flows an illusion? In lucid prose Buonomano presents his own influential theory of how the brain tells time, and he illuminates such concepts as free will, consciousness, spacetime, and relativity from the perspective of a neuroscientist. Drawing on physics, evolutionary biology, and philosophy, he reveals that the brain’s ultimate purpose may be to predict the future—and thus that your brain is a time machine.