"Close Encounters of the First Kind" refers to a classification of UFO sightings where a person observes an unidentified flying object without any interaction. This term was popularized by the astronomer J. Allen Hynek, who developed a scale to categorize encounters with extraterrestrial phenomena. In this type of encounter, witnesses may see a bright light or a strange craft in the sky, but there is no direct communication or physical evidence left behind. Such sightings often lead to curiosity and speculation about the existence of extraterrestrial life and the nature of these unidentified objects.