This is a meandering mess of a book full of bias.
Here are some of the major issues:
1) There is no discussion about the multiple variables that lead to national borders. For instance, there is no discussion about the importance of shared language, shared culture, shared history, or shared moral values in the establishment of a nation. There is no discussion of provincial borders, county borders, city borders, town borders, or family borders. To me, borders are extensions of human nature from the household up. This idea is akin to the philosophical logic of Aristotle and his idea of Zoon Politikon. I can debate this. It's not a simple question. For Baston, however, borders are just artificial impositions by the powerful on the weak and are done by national fascists be they left or right. For him, it is simple. No consideration is given to the other explanatory perspectives like the one I just put forward.
2) There is no discussion about the benefits of borders. Notably, there is no discussion about the security they provide whatsoever. For instance, he doesn't once address why the EU does have borders. It's not a pure nationalistic entity so why have borders? Instead, he focuses on the negatives and pecularities of borders. I don't actually disagree with his points on border people being vulnerable to genocide or having unique identities. He is correct on those points. However, borders also allow people to leave an inhospitable country to go somewhere else more hospitable. He just doesn't get into this point in any meaningful way.
3) There is a real worrying promotion of open borders throughout that is done in a taciturn way. I am not against migration and people living or working in other countries, but border control is essential for that to work without a country wide collapse. If we didn't have border control in the EU, our countries would be swarmed with immigrants because we have an unjust amount of opportunity and money vis a vis other continents near us. The residents of those continents will go to the land of opportunity and money, yet as any European knows, we do not have the infrastructure or jobs to accommodate immigration on this scale.
4) He is extremely selective in what he discusses. This is recent European border history. He focuses on the effects of WWI and WWII mainly. There is no meaningful discussion of Rome whatsoever and its effect on European borders. He is also clearly biased towards Russia and Hungary vs. the EU (minus Hungary) (the paragon of progress per Baston).
5) The book reads like a travellers poorly organised notes dressed up as something intelligent and rigorously thought out. The book is literally the following:
a) Cosmopolitanism is desirable.
b) Boo communism and boo nationalism.
c) Borders are artificial impositions by the evil nationalists and communists on the cosmopolitan poets.
d) Open borders are therefore desirable, so we can all have a poetic picnic together, hold hands, and sing kumbaya.
e) We are all so well off on in the EU (minus Hungary) vs. the likes of Russia. Proof of kumbaya concept per Baston.
Here is one for you, Lewis. If borders are just artificial impositions, why are nationalistic movements growing rapidly currently across Europe? How come the EU isn't the kumbaya poetic picnic you tacitly think it is for so many?
Lastly, he just makes some quite outrageous statements throughout. This for myself stood out:
"History and ethnicity are too slippery to be valid ways of defining borders"
This is just flat-out stupid.
a) You can not define a border in any meaningful way without consideration of history.
b) Conjoining history with ethnicity like this is stupid. They are not comparable variables.
c) He doesn't mention religion or culture as being too slippery to be valid ways to define borders. Why not? I guess from reading this book, and it's over focus on Jewish European history vs. other European religious histories that perhaps Baston would be supportive of a European Jewish state. Just a hunch, though it is based on the way this book is presented.
So yeah, overall, this book is abysmal. It is ludicrously stupid.
He should stick to defining electoral borders.
Avoid.