Fahrenheit 451 by Ray Bradbury
Just re-read this classic, whose title is based on the point at which book paper burns. My distant memory failed to do it justice!
Interestingly, while a near total ban on books is enforced 'top-down', the disengagement with challenging or provocative ideas expressed in any media is portrayed as an end result of popular disengagement in a manic pursuit of 'happiness'. Superficial entertainment approaches the lowest common denominator. Official oppression itself is but a spectacle.
It's only briefly 'post'-apocalyptic but features an interesting, albeit desperate approach to the preservation of knowledge.
https://en.wikipedia.org/wiki/Fahrenheit_451