Paul Davies is a physics professor and popular science writer with an impressive list of titles to his name. While topics that he has covered include biological evolution and Einstein’s theory of relativity, he has given considerable reflection to the question of extraterrestrial life. As a managing member of the SETI program, Davies has invested a great deal of personal and professional energy into answering the question, are we alone in the universe (also the title of an earlier and slimmer volume by professor Davies). In his latest book, he wonders why, after fifty years of pointing radio telescopes skywards, the SETI project has failed to detect a single verifiable signal from an alien civilization. Confronting that dilemma forms the basis for this highly engaging and thoughtful book.