Throy - Jack Vance

The Conservancy of Cadwal has a new Charter- thanks to the courage of Glawen Clattuc and his beloved Wayness Tamm. But this has not brought peace to the people of Cadwal- instead, it has polarized them. Led by exiles, anti-Conservancy forces continue work to open Cadwal to commercial exploitation, while a new extremist faction seeks to restore Cadwal to entirely natural condition. In the middle are the governors of the planet, and their police force. Newly-promoted Commander Glawen Clattuc is charged with apprehending the conspirators wherever they might flee, but he also has a personal agenda. After twenty years, he will solve the mystery of his mother's death.

Throy is part 3 of 3 of The Cadwal Chronicles.
Cadwal is a planet of extraordinary beauty. To protect it, the "Naturalist Society" has set up a Charter which allows only limited settlement on the planet in order to enforce the laws of the Conservancy. These laws forbid extensive human habitations, mining and other exploitation activities. Only six "Agents" and their staff are allowed to reside permanently on the planet: their main function is to prevent other humans from establishing residence, although tourists are allowed in specially designed lodges, overlooking sites of natural beauty and interest.

Cover art by Paul Rhoads & Howard Kistler