At the risk of triggering one or more unanswerable RPG discussions that occur over and over without end, here is a terrific post about unanswerable RPG discussions that occur over and over without end:
https://www.indiegamereadingclub.com/indie-game-reading-club/ten-unanswerable-evergreen-discourses/
*Ten things that will pad out my list of generic rpg book topics. I definitely didn't start with a clickable title and then fumble coming up with the ten things.