What is the author's style in When China Ruled the Seas: The Treasure Fleet of the Dragon Throne, 1405-1433 by Louise Levathes?

As evidenced by the material, Levathes has written with the detached manner and style of a teacher. Her goal, quite obviously, was to encompass the thousand year history of China's dominance on the high seas into one tome. Levathes based her book on eyewitness accounts, official Ming historical documents, as well as on African, Arab and Indian resources.