The Inhabited Island - Arkady & Boris Strugatsky

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.