Close Encounters of the Tenth Kind

Contact situations between humans and non-human intelligent life can be divided into the following categories: The first category is seeing from a distance. The second category is the impact on witnesses or the surrounding environment. The third category is seeing clearly and having some kind of communication. The fourth category is physical contact. The fifth category is mutual cooperation. The sixth category is conflict. The seventh category is relationships or other forms of "combination". The eighth and ninth categories involve large-scale conflicts or extensive exchanges and cooperation with all mankind. Category 10...