Chapter 7 is about Balance Methods:
I cannot stress how important balancing a game is, between all players options/choices every possible decision needs to be fair when compared to all other options/choices in any game, if some cards or characters or whatever is clearly better than others then the game can feel "not fair" and tends to bottle neck strategies into a few favorited "best ways to play" which literally makes all the rest of the games options/choices a waste of everyones time to put in it at all
Fortunately there are many ways to balance games, not just with a bunch of mathematical algorithms that attempt to include every possible angle one could choose or do... thats literally the most difficult way to balance a game actually, by adding a pool of anything and then trying to balance it all out afterwards, it would require tons of play testing and even then most games just get "relatively close"
So i prefer to focus on balance right from the roots, never adding anything unless there was a purpose logically to put it in at all, I will tie theme and art onto that option later but I make sure the internal blueprint is solid first. I compiled a list of about 50 alternative and mostly simpler ways to balance games here.
I also consider games that are deliberately unbalanced because there is more inductive or imaginative ways required to win and some people more enjoy storyline games than deep strategy games, but still must make sure the fundamental mechanics feel fair for everyone for replayability value of the game.