Another novel by Janusz Zajdel, set in a dystopian future. After returning from a space mission lasting many years, the main character discovers that humanity has changed a lot in his absence. As a result of a demographic experiment, society has been divided. Two groups of people have developed - the poor, degenerate and the privileged. Some people live on the moon and the rest live on Earth.
This is a sociological novel so the depiction of society occupies an important part of the book. The author spins a bleak future in which the poor majority must make do with very limited access to resources while the rich and privileged control the rest of society. The main character tries to find his way through this chaos and his overriding goal is to find his beloved. Unable to find her and discovering the dire state of humanity, he decides to travel back in time using the Cylinder of the title. In addition to the love plot (which is not so common in science-fiction novels in my opinion), there are also elements of a technical nature related to possible time travel and its consequences.
The novel is written in the form of a found diary. There are many personal reflections of the main character on the condition of society and its depressing state to which technical development has led. The book is short, but its content is heavily condensed. Nevertheless, there are many threads here. A big plus is the ending, which is centered around the aforementioned issue of time travel.