First of all: there's nothing new. Egremont is just summarizing memoirs of others. If you have read them (and they're worth it!), you'll be disappointed. He adds nothing new.
Secondly, it is rather funny when the author stresses anti-Semitism of British diplomats of the 1920s and 1930s but does the exact same thing when writing about East Prussian lands now, being part of Poland, Russia, and Lithuania. The East is filthy, messy and uncivilized while the West is civilized, organized, and clean. The author makes no references to how these territories were destroyed during WW2 (it seems he doesn't even have proper knowledge), what the early Communists dealt with post-1945 (expelling the Germans, that's true but also dealing with unprecedented destruction), and that in fact the collectivization of rural areas was actually working quite well e.g. in Poland, while the huge blow to the region and a striking poverty are a result of shifting from Communism to Capitalism (the cooperatives were just dismantled and no help was offered to the people, of course it all had to decay).
Third of all, some parts of the book are irrelevant. Really, a whole story of Käthe Kollwitz's son which was in fact written only to focus on a cemetery of British soldiers who died in Belgium in WW1? How is that relevant to the story of East Prussia? I understand that this book is aimed mainly at English-speaking audiences but really, this is over the top.
Moreover, the author has no knowledge of pre-German history, dialects, the mixed heritage of East Prussia up to a point when he rants about changes of names of towns. Dude, if you asked a linguist who really knows the history of language in this region, you would know that Allenstein is the same as Olsztyn, and that they both come from an old Prussian root. In fact today's East Prussian parts which are part of Poland and Lithuania (less so Russia) are full of old Prussian names (many of which were Germanized, also in Nazi times, cause the names sounded too “Baltic” for Nazi ears).
The worst, however, is the fact that this is not a book about East Prussia. This is a book on how an older British man who has aristocratic roots views East Prussia. Therefore, as you can expect, he mainly rants about aristocrats, takes definite pleasure in the fact he knows Marion von Döhnhoff personally, brags about it for 300 pages, and doesn't go below the level of an artist or a professor. He doesn't speak to peasants as if it was below his dignity. To an old Masurian woman in Poland he refers only as “the old lady” (she doesn't even have a name!), if he speaks to a Polish professor, he's nameless as well.
It's funny how one-sided and biased is his view. He mentions Alfred Knox, a British diplomat who witnessed the shift from Tsarist Russia into the Soviet Union and righteously stresses Knox' anti-Semitism. Then he does the very same thing to non-Germans inhabiting these lands today. Communism is one of the main devils here, the author is completely terrified of its very existence (yeah, man, we get it, you're an aristocrat and you're friends with aristocrats. So what?)
Also, it is ridiculously funny when he is shocked and repulsed by how Poles hysterically react to Erika Steinbach, the leader of the Vertriebene in today's Germany. He doesn't go that far to express any sympathy for her but notes that she's been portrayed in one of Polish newspapers in an SS suit, riding on Chancellor Schröder's back. Well, you may be repulsed as much as you want. This book was written in 2011. Maybe, just maybe, someone should deliver a message to Mr. Egremont in 2022 that Ms. Steinbach is currently very much flirting with the neo-Nazi ADf? Perhaps it's not the Poles who are hysterical. Perhaps it's your bias and aristocratic heritage that makes you turn a blind eye to neo-Nazi sympathies and easily focus on the East which is straight from Edward Said's definition of Orientalism?
All in all, 2 stars for literary style. Egremont knows how to write. Stylistically this book is great.
What a pity it's also a reactionary rant of an old man who's not capable of accepting reality beyond the schemes and paths that he's known for decades.
This book should be sold with a huge “Ok Boomer” sticker on it.
Don't be fooled.
Get yourself the diaries of Michael Wieck, Hans von Lehndorff, and so forth.
Egremont is saying nothing that you don't already know from other books. And the evident fear of what's non-Western, Slavic, leftist, and middle to low-class makes this book the most bizarre read I had in years.
Don't waste your money. Don't waste your time.