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The Second Trip is a 1972 science fiction novel by Robert Silverberg. Prior to its publication by Doubleday, it was published in serialized form in Amazing Stories from July to September 1971.
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The Time Hoppers is a science fiction novel by American writer Robert Silverberg, first published by Doubleday in 1967. The plot concerns Joe Quellen, a 25th-century bureaucrat charged with investigating "hoppers", travelers from the future whose presence in the past has been documented for hundreds of years, and his …
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