Mass Market Paperback
Publisher: Ballantine Books (Mm); Reissue edition (Sep 1989)
The fourth and final part of the series after Charon: A Dragon at the Gate. Medusa is a totally controlled surveillance society, yet in the end, it's outside the cities, in the freezing wastelands, that much of this story takes place. The particular quirk here is the ability of the Warden organisms to cause human bodies to adapt to almost any environment, even allowing traipsing around in the snow at temperatures colder than the worst of our Antarctic.
The outer story returns, with the agent attempting trying to avert war with the mysterious aliens. And in the end, there is a massive surprise, as the explanations for all the set-up come out. It's not a particularly happy ending, as Chalker allows his cynicism at the human race to shine through. And so the story concludes.