... then found out that the book was written decades ago.
One problem with books like that is that they might contain outdated information.
Even though I might read books like that and think stuff like "It's not called Czechoslovakia anymore"
But I guess that there are times when I can't tell if something is an outdated fact or not.
When I read a book about Åland just for fun. It was written in the 90's and I'm sure that Åland has probably changed a lot since the 90's. (that might apply for a lot of countries)
I remember though when I read an old Danish book about deaf culture and there was a chapter called "what will deaf culture be like in 2020?"