Writings for young adults were a significant part of Silverberg's production in the 1960s, but faded away for a time while Silverberg concentrated on complex adult themes. In the 1980s he returned to writing books for young adults, this time incorporating complex adult themes into his books for younger readers. Letters from Atlantis and his recent collaboration with Isaac Asimov show this to good effect; Letters from Atlantis invites thoughtfulness even as it excites the imagination with descriptions of a marvelous civilization.

Those looking for the roots of Silverberg's ideas in Letters from Atlantis may find them in his nonfiction. Lost Cities and Vanished Civilizations (1962), Empires in the Dust: Ancient Civilizations Brought to Light (1963), The Man Who Found Nineveh: The Story of Austen Henry Layard (1964), Frontiers in Archaeology (1966), The Morning of Mankind: Prehistoric Man in Europe (1967), Mound Builders of Ancient America: The Archaeology of a Myth...