The authors developed two fantastic models that they present in this book:
(1) First, they have seven dimensions of culture that are AWESOME for understanding the differences between how people view the world. They present it strictly in the international business sense (for example, how meetings can go astray if they include one person from America and another person from Japan). But, I find the model helpful in explaining any cultural differences between any two people (even beyond the business sense, and even domestically). My wife and I are both white, able-bodied people from middle/upper-class families in the United States, but we still see the world in vastly different ways, and this book helps explain some of the differences.
(2) Equally as importantly, they stress that it isn't enough to just understand the differences. That alone can actually lead to MORE prejudice. For example, "Ugh! Now I see why the French are so dumb! They view things as XYZ." Instead, they present a model that I need your differences and you need mine. It's a very asset-based approach. Don't judge people for approaching the world differently than you do, and - in fact - seek out those differences to balance yourself out and learn.