The inhabited island - Arkadii Strugatskii

When Maxim Kammerer, a young space explorer from twenty-second-century Earth, crash-lands on an uncharted world, he thinks of himself as a latter-day Robinson Crusoe. Eager to establish first contact with the planet's humanlike inhabitants, he finds himself increasingly entangled in their primitive way of life. After his experiences in their nightmarish military, criminal justice, and mental health systems, Maxim begins to realize that his sojourn on this radioactive and war-scarred world will not be a walk in the park.

The Inhabited Island is one of the Strugatsky brothers' most popular and
acclaimed novels, yet the only previous English-language edition
(Prisoners of Power) was based on a version heavily censored by Soviet
authorities. Now, in a sparkling new edition by award-winning translator
Andrew Bromfield, this landmark novel can be newly appreciated by both
longtime Strugatsky fans and new explorers of the Russian science
fiction masters' astonishingly rich body of work.