Einstein's Dream is a short, innovative work of experimental fiction by physicist Alan Lightman. I am somewhat at a loss as to how to classify this work- I call it experimental fiction, above it is called a "novella", and it might also be called a prose poem, an anthology or many other things.
What appears to be the framing story of the book is that Albert Einstein, while working on his theory of relativity, has dreams about the nature of time. Each vignette on the nature of time is around five pages, and takes place in Berne, Switzerland. (That the dreams are Einstein's and that the story takes place in Berne is shown from interludes where Einstein appears). Some of the depictions of alternative conceptions of time are taken from possible exaggerations of the theory of relativity, such as where people try to live higher in the mountains so that time moves slower, while others are pure fantasy. Although written by a physicist, the book is much more about the human conception and experience of time than it is about physics.
One of the more curious things about the book for me is that the oddest thing about the book is not so much the depiction of mind-bending temporal realms, but the fact that it portrays early 20th century European life. In the introduction to That Hideous Strength, C.S. Lewis points out that to a modern reader, almost the entire fairy tale is fantastic, but to the reader of the time, wicked stepmothers and woodsmen were fairly common elements. To me, for example, in the vignette concerned with a world where time passes without anything ever changing, the part that puzzled me was the mention of cummerbunds, butter plates and serviettes. I have, upon occasions, experienced time as a changeless ocean; but I can't specifically recall having a plate that is only used for butter. I don't actually know if some small measure of social satire was intended in this book, but at the very least, the combination of fantastic concepts of time and causality with the custom-driven lives of the Swiss bourgeois is humorous.