Anyone alive in the eighteenth century would have known that "the longitude problem" was the thorniest scientific dilemma of the day—and had been for centuries. Lacking the ability to measure their longitude, sailors throughout the great ages of exploration had been literally lost at sea as soon as they lost sight of land. Thousands of lives, and the increasing fortunes of nations, hung on a resolution.

The quest for a solution has occupied scientists for the better part of two centuries when, in 1714, England's parliament upped the ante by offering a king's ransom (£20,000, or approximately $12 million in today's currency) to anyone whose method or device proved successful and reproducible. The scientific establishment throughout Europe—from Galileo to Sir Isaac Newton—had mapped the heavens in its pursuit of a celestial answer. In stark contrast, one man, John Harrison, dared to image a mechanical solution—a clock that would keep precise time at sea, something no clock had ever been able to do on land.

Longitude is story of an epic scientific quest and of Harrison's forty-year obsession with building his perfect timekeeper, known today as the chronometer. Full of heroism and chicanery, it is also a fascinating brief history of astronomy, navigation, and clockmaking. Through Dava Sobel's consummate skill, Longitude opens many new windows on our world.

"As much a tale of intrigue as it is of science . . . A book full of gems for anyone interested in history, geography, astronomy, navigation, clock making, and—not the least—plain old human ambition and greed."—The Philadelphia Inquirer

"This is a gem of a book."—The New York Times

"A simple tale, brilliantly told."—The Washington Post Book World

"Intricate and elegant . . . No novelist could improve on the elements of Dava Sobel's achievement."—Newsweek

"An exquisitely done narrative of the chronometer. It is a wonderful and engrossing achievement."—William F. Buckley, Jr.

"Only someone with Dava Sobel's unusual background in both astronomy and psychology could have written it. Longitude is a wonderful story, wonderfully told."—Diane Ackerman, author of A Natural History of the Senses