It is a light history on the subject. I did enjoy reading the book although I would be careful about quoting facts from it. For example we are not sure what happened to the Great Library only that by 800CE it was gone, whether it was as the writers claim Julius Caesar and the Muslims conquerors later is not clear. Nor was I sure over some of the science quoted i.e., the accuracy of Eastosthenes's calculation on the size of the Earth, although it was a great achievement it might not have been as accurate as the writers claim. I also doubt that Geographica was as important as the writer's claim in opening up the world but it is a nice story.