Longitude by Dava Sobel

This tidy little book sat on my bookshelf for years.  It's short - under 200 pages, and reads quickly. Its subtitle, "The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time" is accurate.

In the early 18th century, the problem of determining longitude at sea came to a head.  Latitude was easier to calculate based on the sun/stars, but the lack of being able to calculate longitude had resulted in many shipwrecks, costing sailors their lives and crowns their riches.  So the English Parliament put out a contest - whoever could figure out a way to calculate longitude accurately would win a cash prize large enough to sustain them for most of their life.

Most "contestants" aimed for a method that relied on celestial bodies, but one man (John Harrison) decided that clocks that kept accurate time at sea would be a more elegant way to solve the problem.  His lifework (and that of his son) became creating such a clock - not a simple feat in the 1700s.

This story - as depicted in the book - is fascinating.  There are the politics, the villains, and the science.  What's most amazing, however, is the intrigue - far more than you'd imagine in what seems like such a dry topic.  A good read.