Dava Sobel's nonfiction book tells the history of the longitude problem in science and navigation. It traces eighteenth-century efforts to solve it and shows how John Harrison's marine chronometer transformed seafaring.

One invention changed the way the sea could be understood.

A science-history nonfiction book about the longitude problem of the eighteenth century and the persistence of clockmaker John Harrison. It presents the breakthrough in marine timekeeping as both a technological achievement and a human story.

A quest to measure longitude changed the history of navigation.