A fun read by a master of Fantasy and Sci-Fi. A new planet, ripe for exploitation, with vast forests and game animals, an intelligent and suspicious native population, a human semi-religious cult that throws one human a year into a volcano for appeasement, and a hateful Christian preacher out to convert the disgusting, reptilian-based natives who dare to call themselves human beings. Throw in a visiting intellectual working on a thesis about native wildlife; there's an interesting story.