This classy book captures the era of scientific advancement in 18th-century Europe and the quest for a way to measure longitude so that ships might no longer become lost at sea. While other scientific greats searched for a celestial answer, John Harrison dared to imagine a mechanical solution--a clock that would keep precise time at sea. Thus began Harrison’s 40-year obsession with what we now call the chronometer. A dramatic human story as well as a fascinating brief history of astronomy, navigation, and clockmaking.