Mark Haddon, author of The Curious Incident of the Dog in the Night-time is interviewed in the Guardian:
"I wrote such bad stuff for such a long time." He owns up to five unpublished novels and says his first, called "The Blue Guitar Murders", might be "the worst unpublished novel ever. But looking back I'm really glad I wrote so badly for such a long time. It is very difficult to be successful as a young novelist because of the pressure to then reproduce it when you often don't know why you'd written a good book in the first place. I've spent half my life under the bonnet trying to find out why things don't work. When Curious Incident worked I knew why because I'd been fiddling with those spark plugs for so long."
Now, I know for a fact that he does not have the worst unpublished novel ever ... because it's surely the one sitting in my drawer!
Curiously incidentally, I asked an Asperger's friend of mine what he thought of Haddon's first book and says he was impressed with it and thought Haddon had got things right.