- The Riverworld is a fictional planet and the setting for a series of five science fiction novels (1971–1983) by American author Philip José Farmer (1918–2009). The Riverworld is an artificial, or heavily terraformed, planet where all humans (and pre-humans) who ever lived throughout history have been restored to life. The novels (and a few shorter works) explore interactions of resurrected individuals from many different cultures and time periods. The underlying theme is quasi-religious. The motivations and ethics of the unknown intelligences that created the Riverworld and its inhabitants are explored.