It’s not an exaggeration to say that “clock time” runs our lives. From the moment our alarms go off in the morning, the clock reigns supreme: our meetings, our appointments, even our social plans are often timed down to the minute. We even measure the quality of our lives with reference to time, often lamenting that time seems to “fly by” when we’re having fun and “drags on” when we’re bored or stagnant. We rarely stop to think about time, but that’s precisely because there are few forces more omnipresent in our lives. “You are the best time machine that has ever been built,” Dean Buonomano writes in his book “Your Brain Is a Time Machine: The Neuroscience and Physics of Time.” Buonomano is a professor of neurobiology and psychology at U.C.L.A. who studies the relationship between time and the human brain. His book tackles the most profound questions about time that affect all of our lives: Why do we feel it so differently at different points in our lives? What do we miss if we live so rigidly bound to the demands of our clocks and appointments? Why during strange periods like pandemic lockdowns do we feel “lost in time”? And what if — as some physicists believe — the future may already exist, with grave implications for our ability to act meaningfully in the present? We discuss what time would be in an empty universe without humans, why humans have not evolved to understand time the way we understand space, how our ability to predict the future differs from animals’, why time during the Covid lockdowns felt so bizarre, why scientists think time “flies” when we’re having fun but slows down when people experience near-death accidents, what humans lost when we invented very precise clocks, why some physicists believe the future is already determined for us and what that would mean for our ethical behavior, why we’re so bad at saving money, what steps we could take to feel as if we’re living longer in time, why it’s so hard — but ultimately possible — to live in the present moment and more.