In late 2017, scientists at a Hawaiian observatory glimpsed a strange object soaring through our inner solar system. Astrophysicist Avi Loeb conclusively showed it was not an asteroid; it was moving too fast along a strange orbit, and leaving no trail of gas or debris in its wake. There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization. In Extraterrestrial, Loeb takes readers inside the thrilling story of the first interstellar visitor to be spotted in our solar system. He outlines his theory and its profound implications: for science, for religion, and for the future of our planet. A mind-bending journey through the furthest reaches of science, space-time, and the human imagination, Extraterrestrial challenges readers to aim for the stars-and to think critically about what's out there, no matter how strange it seems.