Jorg X. McKie is a saboteur extraordinary, one of the principles of BuSab, and the only human admitted to practice law before the Gowachin bar as a legum (lawyer).
The Gowachin are a species of frog-people (in human terms). Their legal practices are based upon the notion of a healthy disrespect for the law: the losing legum may be killed by the winning legum; a client pronounced innocent before the court is torn to pieces by angry spectators; judges may have bias ("if I can decide for my side, I will"), but not prejudice ("I will decide for my side, regardless"); any participant in the trial is subject to judgement, including the judges.
McKie is chosen as a legum for the Gowachin to solve a particular problem: generations ago, a secret, unauthorized experiment was carried out with the help of the Caleban, a species of unparalleled power from another dimension, whose visible manifestation in this universe is as stars, and who provide jump-doors to sentients that allow instantaneous travel between any two points in the universe. The Caleban isolated a planet, Dosadi, behind "The God Wall", and onto the planet were placed humans and gowachin with an unstable form of government, the demo-pol. The planet itself is massively poisonous except for a narrow valley, into which millions of humans and gowachin are crowded under terrible conditions.
The problem which McKie must solve is caused by the Dosadi's nearness to escaping the God Wall. The apparent purpose of the experiment was to subject sentients to the worst conditions possible for survival and see what behaviours and instincts were bred as a response. Now the Dosadis are terrifying creatures with heightened perceptions, intelligence, and drive to survive and prosper; if they were to be loosed upon the universe, they would quickly conquer it. McKie must find a way to prevent the God Wall from breaking, preserving the secret of Dosadi, or find a way to destroy the planet, erasing the original crime with one of greater magnitude.
This novel is interesting to compare with the Dune series, in which the Fremen are also a people who survive under terrible conditions, breeding pure survival behaviours that make them dangerous to the rest of the universe. Herbert's theme of human survival and evolution are explored here.
There are also interesting parallels between the society on Dosadi and that described by anthropologist Colin Turnbull in his book The Mountain People (written in 1972, 5 years before The Dosadi Experiment). That book describes an Ugandan tribe, the Ik, whose conditions are so desperate and impoverished that they also have learned to survive at whatever cost, up to and including the lives of their own families.
This novel is a sequel to Whipping Star.