The Scientific Investigation of the greatest challenge facing humanity: What if UFOs are real? Reports of UFO sightings and strange visitors from the sky go back as far as recorded human history. But it was only in the twentieth century that technological innovation made them impossible to ignore. We see reports on the evening news, accompanied by videotapes of strange objects in the sky taken by eyewitnesses, sometimes in broad daylight. Astronomer and lecturer William R. Alschuler sift through thousands of reports and identifies commonalties: specific shapes of objects that have reportedly been observed around the world; odd maneuvering in the atmosphere; impossible shifts of altitude and acceleration. Assuming that UFOs represent actual alien technology, Alschuler investigates how they may be able to achieve some of the more astounding feats that have been reported. His exploration takes readers through the possibilities of alternative types of travel: fourth dimension, wormholes and black holes, teleportation, antigravity, and faster-than-light drives. Alschuler also explores some of the historical sightings from human antiquity, the phenomenon of alien abductions, and the possible biochemistry of visiting aliens. It's a fascinating tour through the wonderland of UFO sightings and mythos, based on state-of-the-art understanding of the laws of physics-Newtonian, Einsteinian, and quantum - and written in an accessible style for UFO fans and those interested in exploring frontiers of science.