There is an interesting new book called The Spirit Level: Why Greater Equality Makes Societies Stronger. I think the book is interesting for anyone who's trying to understand determinants for human well-being and thriving. Psychologists have known for a long time that situational arrangements importantly affect many aspects of our mental functioning and this book is a great and evidence based example of how this applies on a societal level.
Here is a brief description of the book's content: "Wilkinson and Pickett make an eloquent case that the income gap between a nation's richest and poorest is the most powerful indicator of a functioning and healthy society. Amid the statistics that support their argument (increasing income disparity sees corresponding spikes in homicide, obesity, drug use, mental illness, anxiety, teenage pregnancies, high school dropouts—even incidents of playground bullying), the authors take an empathetic view of our ability to see beyond self-interest. While there are shades of Darwinism in the human hunt for status, there is evidence that the human brain—with its distinctively large neocortex—evolved the way it has because we were designed to be attentive to, depend on, and be depended on by others. Wilkinson and Pickett do not advocate one way or the other to close the equality gap. Government redistribution of wealth and market forces that create wealth can be equally effective, and the authors provide examples of both. How societies achieve equality, they argue, is less important than achieving it in the first place. Felicitous prose and fascinating findings make this essential reading."