This post is chiefly going to be about books that teenagers might like, but do not involve vampires, werewolves, etc.
My first recommendation would be The Mysterious Benedict Society, by Trenton Stewart. The library I frequented kept it in the Young Adult section, while Barnes & Noble put it in with the kids books; but it is not a little kid sort of books, if you understand, not at all indecent of course, but it has mystery, adventure, excitement, and so on. The placement of books in such places is really arbitrary. It’s four hundred pages long, which is an indication of it’s insides. It’s really wonderful, I can tell you, and I’ve read it three times already.
The next recommendation is The Lost World, by Sir Arthur Conan Doyle. Science-fiction, rather funny.
Tolkien’s The Silmarillion, for serious The Lord of the Rings fans. Really serious fans, because this book is kind of slow going and hard to stick to.
The Scarlet Pimpernel (by Baroness Emuska Orczy) is good if you like French history, and Dickens’ A Tale of Two Cities is better.
The Chronicles of Narnia are some of the best books I’ve ever read. They’re quite short, and they do get put in with the kids books sometimes– but as I said, the placement of books is rather arbitrary.
Well, I hope you enjoy!