The Last Unicorn
In The Last Unicorn, Peter S Beagle wanders in and out of reality. He spends most of his time out, but steps back in occasionally to remind the reader that he's not quite taking it seriously.
One of my favorite scenes in the book is when Schmendrick the Magician informs the Unicorn that it could have been worse, he could have turned her into a rhinoceros, "which is where the whole silly myth got started." I think Beagle was checking to make sure that his readers were still paying attention.
This book teaches no great moral lessons - even the villain seems more pitiful than evil. Ideas and themes run through it, but more because a book must contain ideas than because they're really necessary to the story. One of the few ideas Beagle does seem really taken with is that only mortal things can be truly beautiful - and even that he never gets around to quite explaining.
This book reads like a book written by a young man - it kicks up its heels and is full of wandering fancies and fanciful connections. While the ending is bittersweet, the book is full of joy and optimism.
The first time I heard of The Last Unicorn it was read to me. I've re-read it several times since then and, as with all books, it has changed as I've grown older. It is still a book I retreat to, though, when I want a story full of drifting, fanciful characters and scenes that linger in my mind.