Simplify the following text for a Grade 5 native English-speaking person.
Original: City of Illusions is a 1967 post-apocalyptic science fiction novel by Ursula K. Le Guin , set on Earth in the distant future in her Hainish Cycle . City of Illusions is significant because it lays the foundation for the Hainish cycle , a fictional world in which the majority of Ursula K. Le Guin 's Science Fiction novels take place .
Simplified: City of Illusions is a 1967 science fiction book that was written by Ursula K. Le Guin in her Hainish Cycle .