aka Planet of Adventure
In the novels, Tschai is a planet orbiting the star Carina 4269, 212 light-years from Earth. It is populated by three alien, mutually hostile species; the displaced, native Pnume; and various human races, some of whom live as slaves or clients of the aliens. Each of the four novels relates Reith's adventures with one of the species, and is named after that species. In order, the books are:
The insect-like Pnume are the original inhabitants of Tschai. Their history goes back ten million years and they view the invaders as welcome additions to the pageantry on their world stage. They were forced underground by the coming of the more powerful species. Related to them are the Phung, solitary sentient predators with bizarre habits. The somewhat reptilian Chasch arrived a hundred thousand years prior to the tale's start, and are divided into three warring factions, the decadent Old Chasch, the Blue Chasch, and the barbarian Green Chasch. The birdlike predatory Dirdir and the amphibious Wankh (or Wankh) are comparatively recent arrivals and had warred with each other in the past, but subsided into an uneasy peace due to their relative military parity.
The human client races, the Pnumekin, Chaschmen, Dirdirmen and Wankhmen resemble their alien patrons to some degree, due to selective breeding, surgery and the desire of the humans to emulate their respective masters. The Pnumekin are kept docile by drugs; the Gzhindra are ostracised and exiled Pnumekin who act as agents for the Pnume. The religious fiction that their dead are reborn as Chasch keeps the Chaschmen obedient. The Dirdirmen view themselves as degenerate Dirdir and strive to minimize their differences. The Wankhmen, on the other hand, act as the sole interpreters of the Wankh and as a result, are able to manipulate the alien race to their own advantage. Vance's depiction of the human race after tens of thousands of years on Tschai aims to show how foreign humanity can become in alien surroundings.