Robert Silverberg 
Those Who Watch 

‚The explosion was painfully bright against the dark backdrop of the moonless New Mexico sky. To those who looked up at that precise moment – and there were many who happened to look up – it was as though a new star had momentarily blossomed in blue-white incandescence.’Only three human beings would ever know that the blinding flash in the sky on that night in 1982 was an exploding flying saucer. Only they would learn the truth about THOSE WHO WATCH – about the alien observers who came into this world in a crash landing from the stars. THOSE WHO WATCH is the strange, seductive story of three accidental colonists from outer space whose chance encounter with Earth brought revelation to three earthly counterparts – and triggered interplanetary conflict. It is a remarkable story by one of science fiction’s most remarkable writers.