Introduction / P. Anderson -- Prologue / R. Hoskins -- Cold war / K. Neville -- Third stage / P. Anderson -- Gentlemen be seated / R.A. Heinlein -- Jaywalker / R. Rocklynne -- The hated / F. Pohl -- Sunrise on Mercury / R. Silverberg -- Hop-friend / T. Carr -- The man who lost the sea / T. Sturgeon -- First contact / M. Leinster -- Misbegotten missionary / I. Asimov -- The market in aliens / K.M. O'Connell -- The rules of the road / N. Spinrad -- Jetsam / A.B. Chandler.