Hadon of Ancient Opar

Hadon of Ancient Opar is a fantasy novel by Philip Jose Farmer, first published in April 1974. The first British edition was published in 1977. It and its sequel in the Khorkasa Series, Flight to Opar, both purport to fill in some of the ancient prehistory of the lost city of Opar, created by Edgar Rice Burroughs as a setting for his Tarzan series.