From the movements of the spheres to the slipperiness of relativity, the story of science unfolds through the fascinating history of humanity’s efforts to keep time. Our modern lives are ruled by clocks and watches, smartphone apps and calendar programs. While our gadgets may be new, however, the drive to measure and master time is anything but—and in A Brief History of Timekeeping, Chad Orzel traces the path from Stonehenge to your smartphone. Predating written language and marching on through human history, the desire for ever-better timekeeping has spurred technological innovation and sparked theories that radically reshaped our understanding of the universe and our place in it.