I haven't deducted stars, but I warn the reader that the information is dated and often outdated. This book was written in the 80s, in a time of high inflation. Lots of people were speculating in creative (and often loosey-goosey) financing ventures. For example, Mr. Allen cites statistics that show that a large percentage of home purchases are made with creative financing--like 40% or more, though I don't recall exactly. That is not the case today.
Based on the title and the first chapter (which I read in the library before checking the book out), I expected a more general treatment on how to build wealth. The book is mostly about real estate, which is okay, because I'm interested in real estate. But a lot of Allen's schemes won't work in 2015. For example, Allen states that FHA loans are fully-assumable for any investors who can afford the monthly payments and has a heartbeat. That statement became untrue on December 1, 1986, and now many of the schemes in this book will no longer work with FHA and VA loans.
Again, I did not deduct stars, because the information was true at the time it was published. However, the book is less useful now than it once was.