I wanted to like this book more than I did – I have been reading about the Fall of the Western Empire and listening to Roman History podcasts on a more or less continual basis. It isn’t a bad book, but I would have liked more detail in some places and less in others.
The first part of the book is a listing of various ‘turning points’ during the history of the Empire where things could have gone better. These include avoiding the disaster at Teutoberger Wald in 9 AD, which led Augustus to back a fixed Imperial Border, or a more determined counterattack by Tiberius and Germanicus to restore the situation, or if Caracalla was killed before becoming Emperor, or ….
By not picking a single point of departure, the ‘Non Fallen Rome’ is a very vague concept. Is the ‘surviving’ Empire a rump state on the Mediterranean, or a stronger ‘Classic’ Western Empire, or a Rome that conquered Germany and the Balkans entirely and never split, or a world spanning SuperRome that includes Persia and the Americas? All these cases are set up as possible outcomes, but how the change actually happens is left unsaid.
After picking a point of departure, the author usually leaves unsaid how the change is implemented. For example, to avoid the decades of Crisis in the third century, he posits a ‘stronger line of succession’ that somehow magically avoids the decades of the army killing reigning Emperors, naming usurpers, and being more or less helpless in fighting off the Goths and Persians. There were strong Emperors in the period that came to grief – like Aurelian. What did these new emperors do differently than the actual emperors did? This question is more or less evaded.
The latter part of the book explores how a strong Imperial state might change the history of the Middle Ages, including the Vikings, Muslim and Mongol invasions. It gives a good overview of some vital events that the new state would have to face, but since the idea of this state is so diffuse the text is at one point speaking of limited defenses against Muslims and in other places describing annexing Persia and counterattacking into the Ukraine against the Mongols.
I think the book would have been better organized by selecting one to three departure points and following them forward to 476 AD, and then trying to flesh out the changes needed for each to avoid the fall. From there, you could follow these states on through the post Fall events to show how the world would be different, and how long each might last. This book is more or less a partial outline for any such book.