Also, they had mayors and stuff, a VERY clear class division and were technically under the rule of Gondor after the Northern Kingdom fell but Gondor didn't really have the resources or urge to do any ruling over there. Once Aragorn was in they were essentially an autonomous zone under military protection in exchange for maintaining the local roads and bridges.
i've heard of it and it does sound interesting, but i've always been somewhat wary of the LOTR extended universe since being burned by the silmarillion (its so long and my dyslexic ass has a job 😭) - how knowledgeable about middle earth do you have to be to enjoy it? i loved the original books but i'm a bit of a noob when it comes to fingolfin/feanor/etc
the book gives you the rundown in the first chapter, if you know the og story you're good