Astronomers around the world are pointing their telescopes toward the heavens, searching for signs of intelligent life. If they make contact with an advanced alien civilization, how will humankind respond? In thinking about first contact, the contributors to this volume present new empirical and theoretical research on the societal dimensions of the Search for Extraterrestrial Intelligence (SETI). Archaeologists and astronomers explore the likelihood that extraterrestrial intelligence exists, using scientific insights to estimate such elusive factors as the longevity of technological societies. Sociologists present the latest findings of novel surveys, tapping into the public's attitudes about life beyond Earth to show how religion and education influence beliefs about extraterrestrials. Scholars from such diverse disciplines as mathematics, chemistry, journalism, and religious studies offer innovative solutions for bridging the cultural gap between human and extraterrestrial civilizations, while recognizing the tremendous challenges of communicating at interstellar distances. At a time when new planets are being discovered around other stars at an unprecedented rate, this collection provides a much needed guide to the human impact of discovering we are not alone in the universe.