I see Chad’s put a brief review of Dava Sobel’s Longitude up over at Uncertain Principles.

I read the book a few years ago and can confirm that it’s a good read. (I missed a chance to hear Sobel give a talk at a conference a few years back — I was sick (>1.0 dogs) and crashed rather than attend the talk.)

The idea behind Harrison’s solution to the longitude problem (knowing the location of a star and what time it is tells you your longitude) is still with us: ‘to know where you are, you need good clocks’ applies to GPS, too.