DD13 is into history and has been reading a lot of fantasy type books eg Derek Landy. I am keen to encourage him to read something a bit more "grown up" and was thinking about Fatherland. Or there's SS-GB by Len Deighton which I think is being serialised on TV. Could they be suitable for a young teen?
DS is 13 and reads whatever books he enjoys, I don't encourage Young adults fiction. Right now is reading Ken Follett, the Fall of the Giants series . Next I plan to put a couple of Rober Harris books, starting with Enigma.
When I was young, you read children books up to 12 and then normal books, adults books about real life. Zoo station scared me so much at 13 I never touched drugs in my whole life. I have searched for it, but they only have the "new" version, politically correct on many fronts. What made it so damn good was that it was crude, brutal and rough.
Next, I will push forward James Michener (starting with Space maybe) , then transit from the Covenant to the early Wilbur Smith, the Courtney novels and Ballantyne and push it towards Tage. It is fiction, but the apartheid, Rhodesia, the wars are very real. And you have a good chunk of 15/20 books to go through. I wish there was something similar to describe Australia, where we live currently.