Dava Sobel and William J.H. Andrewes.
The Illustrated Longitude (The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time).
Fourth Estate.
1998.
ISBN 1-85702-714-0.

The original book, Longitude, was published in 1995 by Walker and Company, and reviewed by John Dusel in Cook's Log on page 1308, vol. 19, no. 3 (1996). 

The illustrations enhance the story, which makes this version worth having as well.

Ian Boreham

Originally published in Cook's Log, page 1571, volume 22, number 1 (1999).