Use this link for books on Differences in Wealth.
Use this link for books on Money and Higher Values
(Note that not all books in the above lists will be relevant.)
Income Inequality: Is the gap between rich and poor getting wider?
Are We Happy Yet? - by Mark Anielski
Prosperity and Happiness - By Gioietta Kuo
Nation The Happiness of Pursuit. - By Jeffrey Kluger
The Rich and the Rest of Us - John Cavanah
Soaking the Rich Hurts Rich and Poor Alike - by Bob Adelmann
THE FERAL RICH: Time to stop the rich from getting richer, the poor poorer - By Vanessa Baird
Income and well-being: How big is the gap between the rich and the poor?