Robert Silverberg is an American author, best known for writing science fiction. He is a multiple winner of both the Hugo and Nebula Awards.
Silverberg received a Nebula award in 1986 for his novella Sailing to Byzantium, which takes its name from Yeats' poem; a Hugo in 1990 for Enter a Soldier. Later: Enter Another; and in 2004 he was named a Grand Master by the Science Fiction Writers of America.
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[1]: http://en.wikipedia.org/wiki/Robert_Silverberg