Composition: 4/5 
 Evidence: 3/5 
 Writing Style: 2/5 
 Resonance: 2/5 
 Dava Sobel's author biography describes her as an "American writer of popular expositions of scientific topics." This, in fact, gives a good description of Longitude's identity. It is a history of science work, full of well-organized details on the inventors, technology, and politics of the quest to determine longitude. Yet this is also a "popular exposition," thus the tale favors light spectacle over historical depth and a simple chronology over a more nuanced calendar. Many of the leading actors in her book are well-known and already-studied inventors: Galileo, Newton, etc. Sobel's interest in them lies, properly I might add, in their contribution to the puzzle of measuring longitude. Very little new or surprising is added through this background survey, however, and the majority of the book is a brief historical refresher to recontextualize already popular scientific history. Sobel is not a historian and is not presenting new findings. The book is rather an easy-to-read summary, deftly put together. 
 The other juxtaposition that helps to explain what Longitude does is in the title itself. In part, "Longitude" is a book about the race to develop technology that would permit sailors to determine their east/west orientation when away from their home or known ports. The other side of the contrast: "The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time" is a biography of one of the key figures in that race, John Harrison. With regard to the quest portion, I was surprised at how long the longitude problem persisted - it was a real obstacle for the colonial period and a functional solution didn't receive widespread embrace until after the American Revolutionary War. To tell this story though, Sobel must jump around from before the time of Columbus until the later voyages of Captain James Cook. It was neat to see how great scientists over time had contributed to the solution, but it was a lot of ground to cover in a short book, particularly when there is a subtitle with its own objectives. The biographical component gave the book a protagonist to cheer for, a villain to jeer, some heartbreaking moments, and a few opportunities to gloat on behalf of our champion. Yet this portion, too, seemed simple, and Sobel admits that some of the more interesting periods of his life have left no records. Ultimately this portion never would have been sufficient for a biography. Yet the quest was also too superficial for a thorough history of science work. The two put together, though, made for a lightly educational and entertaining read. 
 There were other little eccentricities I noted as well. I found Sobel unnecessarily and oddly flowery with her writing at times, the story would sometimes veer off-topic in order to present some juicy anecdote of a minor character or event, and there was an American-leaning bias to some of the examples and analogies. For myself this compounded my slightly negative inclination as I read. I would much have preferred something with more detail and substance. I did, however, read this with my 9-year old daughter for her home school history focus on European sea-faring. And this simpler history, novelesque plotline, and embellished narration made this more approachable and fun than a dry history text would have been. This was definitely not written for children or as a school text, but it worked quite well for our purposes, and my daughter seemed to have been entertained and to have learned a lot. With or without her, I would conclude that I was happy having read it.