The book had actual garbage advice, live repeatedly suggesting to invest in real state. In contrast to the sensible advice on savings and living below your means, this one was simply "become a real state speculator". When the real state bubble burst, probably a handful of its followers were in a position to make bank from it.

In fact, any author who claims to tell how to become rich, but is still not filthy rich, is a scammer. Most of the content in these kind of books could be resumed in one or two pages, but that wouldn't sell.