The book is concerned with the emergence of those modern states through the troubled history of that region, which included wars and ethnic cleansing, and concludes that national reconciliation and good neighbourly relations are possible even after such difficult events.

[5][3][2] The book touches upon difficult topics such as the nationalistic processes of cultural assimilation (like Lithuanization), massacres of Poles in Volhynia and Eastern Galicia, the Holocaust and the post–World War II forced migrations (such as the Polish population transfers of 1944–1946 and the Operation Vistula).

First, that "particularities of each case" (such as random events and personalities of leaders) are very important, and second, that national identity in the modern world mainly relies on history that is culturally constructed and curated by elites rather than traditions related to "memories cultivated by" small groups.

[1] As noted by Richard Butterwick, the book, while describing said difficult topics, is also positive, as Snyder concludes that "national reconciliation is possible after even the most terrible conflicts".

He called it a "ambitiously conceived and superbly executed", although he cautioned that the book may be "better received" in Poland than in Lithuania or Ukraine due to its "implicit endorsements of Poles as 'elder brothers' and 'mediators'".