It started off like an ordinary day for Dr. Jeffrey Brewster, assistant professor of psycho-sociology at Columbia University. He'd been six weeks old when the first crude satellites were flung into space back in 1957. During his childhood there had been Moon rockets and the space stations - then the joint American-Russian-manned expedition to the Moon in 1965, right after the collapse of the Soviet dictatorship. Mars and Venus had been reached as he grew up and a permanent base was established on the Moon in 1973. Now the day's papers reported that an expedition was ready to leave for Callisto, moon of Jupiter. But Dr. Brewster had a class to make and he was late. That was when the telephone rang and Mari, his wife, said, Long distance from Washington. The caller was Colonel Chasin of Unsecfor - United Nations Security Force, the global and international army that policed the world in these days of relative peace and harmony. Chasin explained that a serious matter had come up, something concerning global security, which he could not reveal at the moment. He ended with, We feel that you can help us, Professor. We'd appreciate it if you'd come down to Washington today and join in a little conference. President Macintyre will be leading the discussion. Brewster couldn't decline - and soon found out that all arrangements had been made at the University for his indefinite absence. What could be going on that required the assistance of a professor of psychosociology? Brewster suspected that the book which had earned him his Ph.D. last year, A Theory of Communication: Notes toward a Mathematical Formulation of Information, had something to do with it. But never would he have suspected what Colonel Chasin told him after his arrival in Washington. On Sunday evening, a spaceship had landed in a Kansas cornfield. An alien being appeared, handed a metal plate to the owner of the farm and said in English that he wanted to see somebody in authority. The United Nations Security Council met in a secret emergency session early Monday morning and worked out a program of dealing with the three aliens. Dr. Brewster was one of the nine men selected to negotiate with the visitors from space The beings seemed friendly, seemed to be here with peaceful intentions, but Dr. Brewster had to find out if they were telling the truth - or the whole truth Here is a suspenseful novel of a tomorrow which may arrive before we suspect its possibility (by the author of Invisible Barriers)."