Kvóta luchyL:

Good morning, I kindly ask to some of the players to explain me why is not present in any of my city the "library" and above all I don't even have the chance to build it, thanks !!

Hello lunchL.
You now only have one library, just like you have only one obelisk. It's in one of your cities or forts, typically the first one alphabetically (it was for me). After you find it, if you don't like the location, destroy it and build it in a city of your choice. You can invest into your library from any location via the new library button (near campaign button). But you can invest into library from kingdom events only in the city your library is in.

They changed this about a month ago.