Peter Jairus Frigate is a fictionalized version of the science fiction

Science fiction

Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

 author

Author

An author is broadly defined as "the person who originates or gives existence to anything" and that authorship determines responsibility for what is created. Narrowly defined, an author is the originator of any written work.-Legal significance:...

 Philip José Farmer

Philip José Farmer

Philip José Farmer was an American author, principally known for his award-winning science fiction and fantasy novels and short stories....

, which appeared in his Riverworld

Riverworld

Riverworld is a fictional planet and the setting for a series of science fiction books written by Philip José Farmer . Riverworld is an artificial environment where all humans are reconstructed. The books explore interactions of individuals from many different cultures and time periods...

 series of novels.

Confusingly, it is only towards the end of the series that the true Peter Jairus Frigate appears - the one in the earlier volumes was in fact an impostor

Impostor

An impostor or imposter is a person who pretends to be somebody else, often to try to gain financial or social advantages through social engineering, but just as often for purposes of espionage or law enforcement....

.

Note that in Farmer's other major series of books World of Tiers

World of Tiers

The World of Tiers is a series of science fiction novels by American writer Philip José Farmer. They are set within a series of artificially-constructed universes, created and ruled by decadent beings who are genetically identical to humans, but who regard themselves as superior, the inheritors of...

, a major character also has the same initials as the author: Paul Janus Finnegan who usually goes by the nickname Kickaha. This character is also a fictionalized (or one imagines an idealized) version of the author.