Given the fact that there are perhaps 400 billion stars in our Galaxy alone and perhaps 400 billion galaxies in the Universe it stands to reason that somewhere out there in the 14billionyearold cosmos there is or once was a civilization at least as advanced as our own. The sheer enormity of the numbers almost demands that we accept the truth of this hypothesis. Why then have we encountered no evidence no messages no artifacts of these extraterrestrials In this second significantly revised and expanded edition of his widely popular book Webb discusses in detail the for now 75 most cogent and intriguing solutions to Fermis famous paradox If the numbers strongly point to the existence of extraterrestrial civilizations why have we found no evidence of themReviews from the first editionAmidst the plethora of books that treat the possibility of extraterrestrial intelligence this one by Webb .