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Eden is a science fiction novel by Stanislav Lem.

A six-person spaceship crew crashes on an unexplored planet. After the crew members manage to escape from the rocket, they attempt to repair the damaged ship and simultaneously begin to explore Eden. Upon returning from the raid, the earthlings discover that a creature has climbed into the rocket and inexplicably launched one of the power units.

During further research and contacts with representatives of the local civilisation, the earthlings discover that there is a government on the planet that denies its own existence. The authorities forbid the study of information theory outside of special institutions, and all public information comes from the dictator and the ruling circles that "do not exist"...

They are also the ones who deny their own existence.