 "Longitude" follows John Harrison s quest to find the key to determining longitude. In the 18th century, the problem of measuring longitude confounded scientists, sailors and politicians. In 1707, unable to determine their exact location through a thick fog, 2,000 men of the British fleet perished by accidentally running into the rocks off the Scilly Islands. As a result of this tragedy, in 1714 the British Parliament passed the Act of Longitude to offer an enormous cash prize to the person who could solve the problem of longitude. A carpenter by trade, Harrison believes that the solution lies in finding a way to measure time accurately, going against many of the scientists of the day, who feel that the mystery would be solved through celestial navigation. Harrison designs and creates four increasingly refined timekeepers. This work takes him through 30 years of struggle and determination (not only his but his family s, friends , and allies  as well) to solve what was referred to as the "greatest scientific problem of the time." Along the way, he faces the animosity and interference of many of the celestial navigation proponents.