Someone once said, "I made myself wealthy by reducing my wants." That's what this book says. Sure, the content is padded quite a bit, but the message is worth what the book costs, whether you are an shining example of this philosophy or an opponent of it: you can spend or you can have, but most of us can't do both.
I agree with other reviewers' comments that the authors found most wealth was accumulated through operating small and boring businesses in your own neighborhood, yet don't recommend this to their readers (nor do those self-made millionaires, in most cases.) And their research methodology is a bit suspect, since it seems to have presupposed that source of wealth in finding interviewees. Still, I agree with the formulas that describe whether you're building an expected amount of wealth based on your age and income.
Bill Cosby, no financial slouch himself, said "The secret of wealth is ownership." This book gives you plenty of examples to help you believe that. It's not what you spend, but what you save, that gives you real independence. It's encouraging to read (maybe in a masochistic sort of way) that lots of high-earners (doctors and athletes, for instance) blow those high earnings and have little to show for it, living (large) paycheck to paycheck. Others, far less educated and with smaller paychecks, quietly avoid wealth-losing expenses such as flashy cars, big houses, and fancy clothes, to succeed in the only true measure of personal wealth: a high net worth. It isn't what you earn, it's what you keep.
I read the book straight through, hooked on almost every word. Where else can you get inside information on people's personal finances and the decisions that led them to their particular state? Maybe the research wouldn't pass close academic muster, but the individual vignettes are fascinating anyway.
So, negatives aside, I think this book is a must-read. You may fault some aspects of it, but the message is one that everyone should consider, even if you find reasons to ignore its conclusions. And if you're a tightwad, you will rejoice in finding vindication of your choices. But then again, if you're that tight, you'll probably read it from the library anyway!