A tour of clocks throughout the centuries—from the sandglass to the telomere—to reveal the physical, biological, and social nature of timeWhat is time? This question has fascinated philosophers, mathematicians, and scientists for thousands of years. Why does time seem to speed up with age? What is its connection with memory, anticipation, and sleep cycles?Award-winning author and mathematician Joseph Mazur provides an engaging exploration of how the understanding of time has evolved throughout human history and offers a compelling new vision, submitting that time lives within us. Our cells, he notes, have a temporal awareness, guided by environmental cues in sync with patterns of social interaction. Readers learn that, as a consequence of time's personal nature, a forty-eight-hour journey on the Space Shuttle can feel shorter than a six-hour trip on the Soyuz capsule, that the Amondawa of the Amazon do not have ages, and that time speeds...