Cylinder van Troffa

Van Troff's Cylinder (Polish: Cylinder van Troffa) is a social science fiction novel by Polish novelist Janusz A. Zajdel. The book, published in 1980 by Czytelnik, covers the problems of time travelling, society development, eugenics and isolated societies. At the time of its release it was treated as a warning for totalitarian systems.

The plot covers a story of a group of astronauts who are approaching Earth after a 200-year-long journey on a long-distance spaceship called "Helios". Instead of reaching Earth, they are communicated by people living in the Moon's underground colony, and convinced to land there. After landing they get isolated, and they quickly find out that the colony is ruled by an authoritarian regime, which tends to control all the people living there by means of censorship from one hand, and denunciation from the other one. Also, to make the colony's population stable, there is strict birth control there, and people over the age of 60 get "retired", which in fact means senicide.

The colony's officials give vague explanations to the reason on why "Helios" has been diverted to land on the Moon instead of on its original destination, Earth. Initially it is only said that it is "not feasible", or "pointless" to go to Earth now. Gradually "Helios"' crew find out that the Earth's population underwent some process of degeneration (the cause, however, not being revealed), that the Earth's inhabitants are expected to die out quickly, and that the Moon colonies were constructed as a sort of asylum for the non-degenerated part of humanity, which is also expected to recolonize Earth when the crisis will have ended. The crew, however, can already see that the Moon's inhabitants are undergoing some degeneration process as well (skeletal, due to lighter gravity on the Moon, but also mental due to living permanently underground, which leads to chronic agoraphobia) and this finding in turn casts doubts on the planned recolonization. Also, they find out that even the regime itself does not know about the current situation on the Earth, because any bilateral communication was cut long time ago.