Drawing upon Yuen's dissertation, this book -- at the start overall, and by sections -- tells you what it is going to demonstrate and then does it, making it very clear and organized.
I remember first adding it to my reading list when there was discussion about the reasons diversity does not happen, and no matter what examples you gave of films with diverse casts doing well or films with white casts flopping, there was always someone giving a reason why that was a fluke and it was all about profits, and doing what would make money. As it is, some people may prefer racism to financial success, though they may be in denial about that.
What sticks with me most is the stories of working actors having to choose between working and taking jobs that are soul-killing, not always but too often. And while the actors may be a small percentage of the population, what they put on the screen matters for those who do not see themselves, or only see themselves portrayed as crude stereotypes, and it matters for even those who get plenty of representation of themselves, and thus come away with a skewed view of the world.