Lem has been delighting European readers of science fiction for two decades, and has recently garnered laurels in the U.S. … Though A Perfect Vacuum is not primarily science fiction, the blurb-writer who maintains that Lem "here breaks away from the science-fiction mold" is not strictly correct either.

Of the reviews of nonexistent books that make up this volume, most play with Lem's favorite speculative fiction themes: cosmology, cybernetics, probability, and the confusion of subjective and objective realities. Some of the most successful pieces come from this group, such as Non Serviam, a "book" detailing experiments conducted on personoids, rational entities created by scientists within the mathematical matrix of the computer, and allowed to develop their own culture and cosmology within that universe. Lem's cosmic irony manifests itself in the theories and faiths these personoids formulate to explain their existence, and in the troubled nonintervention of the Creator...