A Perfect Vacuum was a collection of humorous reviews of nonexistent books, satirizing trends and fads in literature, criticism, academia, and popular science.  Imaginary Magniture is really a companion piece, being a collection of introductions to books of the next century.  The introductions are parodies, satires, and miscellaneous bits of speculative whimsy, and Lem shows signposts along the way to tell us in what spirit we should take the introductions:  two of the authors are named Rambellais and Gulliver, reminding us that the shadows of Rabelais and Swift cannot be far away.

Joseph Francavilla, American Book Review