I was kind of hoping for some maps showing the influence of the Soviet Union’s westward displacement through Central Europe after WWII. They took bits of the Eastern frontiers of Poland and Czechoslovakia and then gave those countries chunks of German as compensation. The mass displacement of people because of these border shifts was unprecedented. Pretty much anyone of German ethnicity anywhere in Central Europe that wasn’t Germany or Austria had to move to Germany or Austria. The Eastern border of Poland was always kind of fluid so I don’t think there was that much westward movement there (beyond the anti-Communists who fled Eastern Europe in general in the 1945–8 period). I don’t know about what happened with the people who lived in the parts of Slovakia that became part of Ukraine. Czechoslovakia was always kind of oddly agglomerated country, so I don’t think many, if any of them would have traveled to the new Czech lands in the West and after the split of Czechoslovakia in 1993, thanks to the westward expansion of the USSR they ended up with less territory since the internal boundary between Slovakia and the Czech Republic remained the same through all of this.