Is mankind alone in the universe? Will we ever encounter intelligent life beyond Earth? These questions have been asked for centuries. Recent advances in the fields of astrophysics, astronomy and astrobiology make it more likely than ever before, that Earth may not be the only inhabited planet, and that humanity may not the only intelligent species in the universe. What would be the consequences of contact with an extraterrestrial intelligence? This question is at the heart of the emerging discipline of exosociology. According to the authors, first contact with an extraterrestrial intelligence poses enormous risks for humanity. These risks come not only from extraterrestrials, but above all from ourselves. We should be prepared. Michael Schetsche and Andreas Anton's comprehensive introduction to exosociology was first published in German in 2019. The book has been widely acclaimed in Germany and internationally. It is now available in English for the first time.