Philip José Farmer states in his various introductions that the series evolved and took many forms. The River of Eternity is the best published, self-contained version of the series’ inception. The five “mainstream” novels, to use Farmer’s term, depict his vision of humankind as essentially a proud, quarrelsome, and warlike people with rare and seemingly futile attempts at spirituality or selflessness. This vision, seen through a variety of alternating perspectives, rises to a logical climax in The Magic Labyrinth, a novel originally part of The Dark Design but made into a separate book because of the adventure’s length.

The series’ themes, first and last seen through the eyes of Richard Burton, are underlined in The Gods of Riverworld. In that book, Burton, who has seen and learned more than any other human, decides to continue adventuring rather than develop spiritually. The Magic Labyrinth was intended to be the final volume, but The Gods of Riverworld became the mainstream series culmination, emphasizing the added themes of the corrupting nature of power and the ultimate restlessness of the human spirit, which is not satisfied even with all questions answered.

The impressive, cohesive series has earned critical praise for its wide scope of morality plays interspersed with adventure plots. The series is considered to be on the same level of importance as Isaac Asimov’s...

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