L. Sprague deCamp 
Tower of Zanid [EPUB ebook] 

Welcome back to the planet Krishna — a wilderness of blue woods under three moons, where square-riggers sail the treacherous inland seas, where fierce humanoid natives with feathery antennae cross swords in endless war, and where a Terran outside the confines of the spaceport is strictly on his own!The Tower of Zanid is the seventh book of L. Sprague de Camp’s Viagens Interplanetarias series — interplanetary romance in the tradition of Edgar Rice Burroughs’ Martian Tales.