If the Universe is Teeming with Aliens... Where is Everybody?: Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

In a 1950 conversation at Los Alamos, four world-class scientists generally agreed, given the size of the Universe, that advanced extraterrestrial civilizations must be present. But one of the four, Enrico Fermi, asked, "If these civilizations do exist, where is everybody?"