I dont really understand the complaints in other reviews, the book is not a recipe book per se (and it doesnt claim to be), it is a discussion of how diversity can be implemented in gaming and the challenges diversity presents. Also of course how diversity issues can be used to drive campaigns. And I think it does that extremely well.
The text is short, I dont remember exactly how long but readable in a couple of hours and as such obviously does not cover all possible scenarios nor really inform on how a diversity oriented campaign or characters should be used, rather it gives thinking points, pitfalls and other info which might be used by a GM to develop those things themselves. If for example a GM wishes to have a campaign based loosely on a refugee situation, perhaps using goblins as a metaphor for misunderstood foreign refugees and to model issues of mistrust, injury, differences in religion, aceptance of foreigners, how to represent these things on charisma rolls etc then this is the resource to use as a starting point. If one simply wants to have some female characters and a way to make those characters noticably different but still balanced, this booklet describes how this might be done. Has a GM thought about the racial makeup of their world? Some 5% or so of characters might be gay, how do you use that to provide richer more interesting characters, without falling into stereotyping or contrived and hard to believe backstories. If its a grimy dark ages storyline, with war and suffering everywhere, do you have representation of the victims or is everyone living as happy as larry fit and healthy in idilic villiages which is somehow incongruous with the butchery going on supposedly arround them?
Look at this work as what it is. A collection of ideas, pointers, talking points and inspiration. Implement it ad hoc, as required and as makes sense in your setting. For the handful of dollars you might pay, it is well worth it as a useful resource.
[5 of 5 Stars!]