Americans do not know much about the history of Central Europe, this despite that fact that a majority of Americans have at least some ancestry in the Holy Roman Empire or the lands run by princes of the Empire.
Let me list them – Germany, Austria, Poland, Hungary, Czech, Slovakia, Slovenia, Romania, Italy, Switzerland, France, Belgium, Netherlands and even Luxembourg. You can include Spain and Portugal and their empires, since Holy Roman Emperor Charles V was also king of Spain. Pretty much everybody.
I would not recommend most people read this whole book. There is a lot of the one-thing-after-another type of history. But there are some good insights.
For example, the author contrasts the German concept of freedom with that of British (and by extension Americans). The Germans were more corporatism in that they held more to people having rights with their association. Modern progressives with their emphasize on identity and group rights would be at home here. This contrasts with the classical liberalism, that talks about individuals and mobility. The corporatist were not fond of free markets, but they did think a lot about social justice.
Another thing to recall is the multinational, multilingual and multi-ethic character of the Empire. We look back from the nation-state perspective and forget that for much of history the kind of nationalism we know today did not exist. The nobles had loyalty to their prince. It was maybe more like a modern business firm. A person, could – and did – change jobs. The peasants and townspeople were loyal to their own local communities.
The languages they spoke were also local. Linguistic boundaries were soft. As people wandered farther from home, it got harder to understand. Educated people often communicated in Latin. Nationalism is largely a creation of the last few centuries.
In some ways, we may be going back to the future with transnational organizations. The author compares the Empire to the EU. They are very different, but they share some thing in common.