"An interesting piece of sociology"
As someone with a degree in economics, I found "The Millionaire Next Door" very interesting with its various methods of evaluating how the 'wealthy' behave. The book provides some great examples of varying perceptions of utility. In fact I have used the buying cars by the pound example more than a few times. Not suprisingly, the vast majority of the millionaires studies subscribe (perhaps unwittingly) to the bathtub theory of economics... make sure that more money is coming in than going out. Unfortunately not enough people follow this sound piece of advice.
As an entepreneur the study of the small business owners were fascinating. I'm still reeling from the fact that scrap metal is the number one producer of millionaires in this country. I passionately recommend this book to anyone that is looking to start their own business. I know that I wish I had read it much sooner than I did.