Who is Galileo/Newton/Kepler/Cassini from Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time and what is their importance?

Galileo, Newton, Kepler, and Cassini were famous astronomers, who played a large role in the pre-history of this book. These men not only struggled and failed to solve the problem of Longitude (making Harrison's achievements all the more impressive), but they laid out the path towards a lunar distance method that was championed by later astronomers.