Well... I'm currently reading one about Danish kings and queens.
Sometimes I also rent non-fiction books from the library.
I often read ones about things that interest me, even though other times, I just pick a random one. There are also times where I pick a book, based on mood.
Sometimes the non-fiction books that I read are old, so I feel like some of them might have information in it that are outdated.
Like when I read a book about Åland, and it was written in the 90's, I think. And I'm sure that Åland has changed a lot since the 90's. (Heck, and I have even seen how my own country has changed since the 2000's)
I found it a bit funny when I read an old book about deaf culture and there was a chapter saying "How is deaf culture going to be like in 2020?" ...
But I mostly read fiction books.
Heck, so far I have read 90% fiction this year.