Philip José Farmer (1918–2009) was an American author known for science fiction and fantasy novels and short stories. His fiction included the World of Tiers and Riverworld sequences, which blend speculative adventure with questions about identity, society, religion, and human possibility.

Farmer also wrote playful pseudonymous works presented as if by fictional characters, extending the imagined lives of figures from popular adventure fiction. His career included magazine stories and novels, and he received major recognition within the science-fiction community, including multiple Hugo Awards.