The Sixth Kind of Contact

Class Zero Contact: Distant sighting Class One Contact: Close-range sighting Class Two Contact: A part of the body touches them, or one sees traces left by such contact Class Three Contact: Direct physical contact; seeing them clearly Class Four Contact: Communicating through telepathy Class Five Contact: Making friendly contact with their civilization Hao Suwei and Jiang Yang somehow evolved a form of contact that surpassed all five classes: Class Six Contact.