Genre Definition and Recommendation is a feature where I will define a genre and a sub-genre definition and the make some recommendations.
Science Fiction - Definition found on Wikipedia
Science Fiction- is a genre of fiction dealing with imaginary but more or less plausible (or at least non-supernatural) content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities.
Definition found on Wikipedia
Post-apocalyptic fiction is set in a world or civilization after such a disaster. The time frame may be immediately after the catastrophe, focusing on the travails or psychology of survivors, or considerably later, often including the theme that the existence of pre-catastrophe civilization has been forgotten (or mythologized). Post-apocalyptic stories often take place in anagrarian, non-technological future world, or a world where only scattered elements of technology remain.