That was the title of a major book by Joel Primack and Nancy Abrams. We discussed it with them in 2006 and went for the very big picture. Primack, of the University of California at Santa Cruz, is one of the world’s leading cosmologists and happens, as well, to be one of the discoverers of “dark matter.” What do you know about the origins of the Universe, about its size and total content, about its future and, incidentally, about the possibility (likelihood?) that there are other universes, perhaps an infinity of them? The facts and possibilities are laid out here as Primack and Abrams make it sing and zing for you!!