A charming, witty novella by Alan Lightman, containing fictional "dreams" that Albert Einstein might have been dreaming when he was working as a patent clerk, writing his theory of relativity.
This is one of those mind-warping books, that permanently change your brain while you read them, bending your outlook on the world around you. A must read for anyone with any small modicum of intellectual curiousity, quite satisfying and interesting at the same time.