While I try and think of some more books for young adults, I want to suggest a few book that weren't written for children at all, but which I think would make good additions to a library catering for teenagers. It is a very personal list and features many of the books that I read when I was in my late teens (though some I did not read until later).
Some of these book will already be in the library of course. I recommend them - to teachers as much as to students - simply as an encouragement to read them without the off-putting sense of awe that comes with being a 'classic', even a modern one.
John Wyndham's Day of the Triffids is a brilliantly realised nightmare in which the world is suddenly invaded by murderous plants. The idea of someone waking to find the world utterly changed has been explored many times, but seldom better than in this book.
The Outsider. Another book about violence by fellow existentialist, Albert Camus. But this time the violence is arbitrary, casual and senseless. Somehow that theme also seems only to have gained in relevance and pertinence. Camus was arguably the best writer of the existentialists and this book is superb.
The Old Man and the Sea. The French existentialists admired American writers like Hemingway for their spare prose. This book really grabbed my imagination when I read it at school, with its fable like story of an old man, a boy and a very big fish. . .
Goldengrove/Unleaving. Another book about a teenage heart muscles being tested, but this time in the very English setting of Cornwall and by Jill Paton Walsh. This book was recommended to me by Suzanne Jones some time ago and is one of her favourite books. What a lovely piece of writing it is.
Dr Jekyll & Mr Hyde. R L Stevenson is bit of a hero of mine. He wrote such a range of books and of such high quality. The idea of a man physically transforming into another version of himself seems timeless, as all the very best ideas do.
This is a classic book about cowardice and bravery in the face of battle. Stephen Crane's book is set in the American Civil War but will be endlessly relevant. The red badge of courage is a wound, of course.
It is hard to believe that one man could have as many superb ideas as Philip K Dick managed to have in his career. Practically everything he wrote seems to have been turned into a movie, and Do Androids Dream of Electric Sheep? is no exception - it was the basis for the movie Blade Runner. The book is much more thought-provoking though, full of amazing ideas and images.
Dracula. I have returned to this book often since I first read it when I was fifteen or so. I read it after seeing Bela Lugosi in the title role in the 1931 Universal Pictures movie version on TV. But the book is far stranger and darker - distasteful even - than any movie version you will see.
I Am Legend. For a more modern take on vampires - Ricard Matheson wrote the book in the 1950s - have a look at I am Legend. It is brilliantly written and utterly terrifying. Is it horror? Is it sci-fi? Who cares? It is a wonderful piece of writing that will make you think whilst scaring the pants off you.
I read Frankenstein by Mary Shelley at about the same time as Dracula (and like that book, one I have re-read several time). Everyone thinks they know this story because it has been filmed and copied and spoofed so often. But this is a very different beast from the movie versions. If you have never read it, almost all of your preconceptions will evaporate as the story opens on board a ship surrounded by Arctic ice. . .
And while we are on this horror theme, I will point you in the direction of Edgar Allan Poe. His stories can be a little florid, but that just adds to the weirdness. You will rarely read anything as dark and disturbing as The Tell-Tale Heart, The Black Cat or Berenice.
I have praised Saki before on this blog, but that isn't going to stop me doing it again. His stories range from horror to humour (usually black). They are very English and often feature children rebelling against authoritarian adults. They can be very dark. Short story collections are a good introduction to all kinds of writers.
I think Italo Calvino is a superb writer, but I am aware that he tends to divide opinion. I think some people find the books too contrived - too knowing. But that has never bothered me. I find his writing magical and thought-provoking and just incredibly clever. This is one of my favourites.
My Family and Other Animals. I read Gerald Durrell's novel of his childhood on Corfu to my son recently, expecting him to love all the nature references in it, but it was the comic episodes featuring Gerald's crazy family (including the novelist Laurence Durrell) that most amused him (and me).
I read all the Conan books when I was a teenager. I came to them via the Marvel comics series. One of the strokes of genius was Howard making Conan a bit dim. It gives the reader a different kind of relationship with this barbarian freebooter than we would otherwise have.
Susan Hill's novel is about children rather than for children, but it has increasingly found itself onto school set texts because it is such a powerful, gruelling study of bullying and child-to-child cruelty.
James Joyce? James Joyce? Am I really recommending James Joyce to teenagers? Yes I am. I once did a writing workshop with eight year old children based on the last few paragraphs of the last story in this collection - The Dead - with great results. They didn't know they were supposed to be scared of James Joyce. That story - with its story within a story of the poor, doomed Michael Fury - is one I regularly return to and the ending is one of my favourite pieces of writing.