This is one of the best non-fiction books I’ve read in a long time. Harper synthesizes the latest climate, archaeological, and DNA research to tell the story of the influence of disease and climate on the fall of Rome. He avoids the trap of saying climate or disease “caused” the fall. He does claim that they weakend the empire and that at some point they combined with political factors to rob it of its resilience. He also points out how an earlier benign climate, specifically the “Roman Climate Optimum” from 250 BC to 450 AD contributed to the success of the Roman Empire.
The breadth of this book is remarkable; I learned new (to me) things about history, geology, climatology, astronomy, and biology. But he never ignores the human factors of fails to focus on how climate and disease affected individuals as well as the empire.