At the end of George Pal's 1960 classic "H.G.Wells' The Time Machine," the main character returns from 1899 to the year 802701 to rebuilt civilization. Mankind has forgotton about science, religion, technology, art, agriculture, everything. After he has left, his housekeeper notes that the only things the time traveller took with him are three books. She asks his best friend if that seems important.
"I suppose not," he answers. "Only, which three books would you have taken?"
Well?