Einstein's Dreams, by Alan Lightman

This is a fictional collection of stories dreamed by Albert Einstein in 1905 when he was working at the patent office in Switzerland, while also building his theory of relativity. Between brief interludes where Einstein spends time with his friend Besso reporting on his progress, we enter his dreams and the many worlds he imagines, with the many possible forms that time can take. In one world time is circular, everything keeps repeating endlessly. In another, time is simply images. Or it is a sense. Or goes backwards. It is not continuous. A world in which there is no causality. A world in which time results in order.  A world where we live only for a day. A world in which we cannot conceive of a future, every moment lived as if it were the last.

Alan Lightman has constructed a fascinating metaphysical novel in which you find yourself floating gently, as if in a trance, from one world to another, each seeming strange, set against your own notions of time. And you have to ask yourself what is it you know for sure, really, about time or the nature of human existence? Utterly enchanting.

Einstein's Dreams, first published in 1994, has been translated into more than thirty languages, and more than fifty independent theatrical and musical productions around the world have been based on it.