DNF. I'm sorry but it's unreadable. Another reviewer pointed out that even just managing to get a manuscript published these days is worth noting, so there's that. But this stuff is so incongruent, and just jars the mental appliances of science, technology, history, social culture and advancement, and, let's face it, religious disagreement.
The MC is a much-lettered (many advanced degrees) engineer with a somewhat checkered pattern of military promotion regardless of time-in-service and time-in-grade strictures. One doesn't go from being a "Butter Bar" second lieutenant (the lowest officer grade) to a General, one star or above (think Patton or McArthur for modern equivalences) within a few short years. Also, there is a timeline oddity, if age is a determining factor-between serving in WW2, then Korea, then Viet Nam. The guy would be 60+, if the math is correct. Far too old to be in-forces for Viet Nam. I know this because I was stationed in-country, at Long Bihn, in 1970. I was 20. That war was over by 1973.
Now that's a moot point for anyone not a veteran or interested in understanding armed forces structure and staffing, during the cold war era. I put it out there because it made some jarring conclusions as to the research done to promote the story development.
I thought there was some oversight and some stretching of the imagination, but that's what a good story is supposed to do. In this sense, this makes the concept of good story-telling farcial. It felt that I was reading insert material, designed to fill copy page requirements, not flesh out a tale of time-travel or reincarnation. IF that's what this was supposed to be. That conclusion was never reached.
The text reads like an advanced reference point summation for an undergrad engineering student. MC has every degree imaginable. Has 'been there and done that', for literally every life experience. Including finding himself dismayed at the failure that is the Peace Corps. In that, I tend to agree. But that's a political and social statement, so not germane to the book, per se.
My point is that the MC never does anything. He simply thinks it should be thus and so, and it comes into being. Simple blacksmiths perform complex mathematics, construction of implements take but a day or so, construction of roadways, septic systems, carriages, temples, castles, and schools are so simplified that they happen almost overnight. This is a nice idea, but just unrealistic. Even a time-traveler with advanced skills and knowledge would have to present concepts and ideas, source materials, create labor pools and develop records systems, in the moment, not bring systems that haven't been conceptualized for 1000 years to the more primitive pre-millennial era and have it all be immediately successful. It wasn't realistic. It wasn't even primary fantasy. I was disappointed.
Finally, there was simply zero character development. No one questioned the new "Baron". No one argued that the church suspected (as they would) witchcraft or devil sanctioned behavior. No one thought to oppose the changes or subvert power for their own causes. Everyone just went along because it was suggested? Nope, not buying that.
There was very little interpersonal communication and almost zero discussion of alternative processes. No one seemed to have any opinions, and more importantly to my point of view, no one seemed to have difficulty learning the concepts, processes, structures, policies, or programs. Once it was demonstrated, it was done. How did that happen? Was no one a bit odd, or slow to understand, or angry to be seen as possibly lower on the totem pole? How did the social strata function, with 100% agreement, 100 % of the time? It wasn't logical.
The people in the book are flat, one dimensional and boring. If they're dirty on Monday, they're suddenly clean and spiffy on Tuesday. If they can't read or write on Wednesday, by Thursday they are composing their own ledgers and diaries. On Friday, if they are suspicious, by Saturday, they are convinced. It's just not congruent with the theory of change and acceptance by a populace. Learning takes place in a vacuum; but this population lacks the very essence of needing knowledge until the modern concepts are presented, and then by miracles unknown, everyone goes along because they suddenly understand their ignorance. It just made reading awkward and unconventionally odd.
Others have pointed out the editorial flaws and mishaps so I won't belabor the points. To be blunt, if there were editing efforts, they failed. There couldn't have been much stress applied to the editing, because the text is choppy and sloppy. Grammar and poor spelling, along with the assumption that the language spoken in 700-something Cornwall is English is just poor research. As for geographical names and places? Who did that research? They need to go back to school.
I can't finish this book, and I won't bother to read further into the series. I am not a stickler for details, but I do like some accuracy and some well-formed literary structure. I prefer fictional settings, not theories of engineering or combat formations.
If there were a story here, I missed it.
Not for me.