It makes the (to me) convincing argument that geographic determinism, while important, doesn't really explain why the western core given that the eastern core surpassed the west on many measures after the fall of Rome. (Though it does explain why one of those two cores were probably ordained to win out.)

But the western core was in a better situation to exploit the Industrial Revolution which basically made everything before it almost irrelevant.

Neither book does much to explain why well-positioned modern states, e.g. Argentina, weren't able to better take advantage of their position and natural resources however.