The Cadwal Chronicles (in Russian)

The Cadwal Chronicles, Russian translation. All three books in one volume
At the remote end of Mircea's Wisp, far out on the galaxy's Perseid Arm, is the Purple Rose System, containing the three stars Lorca, Sing and Syrene. Around Syrene swings the spectacular planet Cadwal, which the now defunct Naturalist Society of Earth long ago chartered to forever protect from exploitation. Cadwal is administered from Araminta Station - where young Glawen Clattuc wonders what the future may hold for him in the hierarchic, constrained society of Cadwal. His budding relationship with the lovely Sessily Veder ends with her mysterious disappearance, casting Glawen into a strange adventure, and the unraveling of a potent conspiracy.
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.