Bizarre, puzzling, and complex are a few of the many adjectives used to define extraterrestrial encounters with humans. This essay explores some of the complexities of this fascinating phenomena. Included in this essay is a description of the standardized encounter categories, the various theories and beliefs attempting to explain close encounters, a brief chronology of the different types of aliens and their origins, and the testimony of worldwide prominent individuals regarding extraterrestrials and their visitations to this planet. This short but informative article will leave readers with a clear overview and a better understanding of extraterrestrial encounters, a most challenging phenomena of our time.