A book originally published 85 years ago (1929) now functions as a part of history as much as a telling of it. I found Clark's side comments on education and philosophy slightly amusing from the other side of the 20th century. Other points stand: that 17th century Europe saw at most 7 years of complete peace (and even then, the years were neither consecutive nor entire); and his concise observation about the changing concept of frontier or border. Most striking is the assumption of what an educated reader will know. Aside from the untranslated Latin, French and German, one must run to the reference books for many an aside that would have been common knowledge (of the educated) before WWII.