Recently read The 4-Hour Workweek, Expanded and Updated by Timothy Ferriss.
It's much like Rich Dad Poor Dad by Robert T. Kiyosaki and Sharon L. Lechter (ghost writer) in that if you follow the exact advice (provided you even can), you will most likely get the results quasi-promised.
But I doubt that most people can or would want to do what these guys do, particularly if you have kids. Plus, both of these guys seem to have made most of their money in self-promotion and just a bit by actually doing what they advise.
Ferriss even admits in his book that his sports nutrition company was failing until he freaked out and ran to Europe to hide, all the time expecting a call that it had gone under. Lo and behold, while HE wasn't running it, it turned into a profitable business, which means someone working for him fixed things while he was having his hissy fit. (Please note this is my interpretation of the events he relays in his book, though he also admits in the book he's good at starting a company, but bad at running one.)
No surprise, one of his bits of advise to achieve a 4-hour work week is: have someone else do the work. So, to pound it to China, his central advise is to start up a company that has little overhead or inventory, then stand back and let your lackeys run it. Wow, huh? (And, of course, write a book about it and hope it sells a lot.)
Speaking of China, he won a National Chinese Kickboxing Championship by exploiting a rule where pushing your opponent out of bounds equates to a technical knockout. Do that three times in a match and you win, which he did. Also consider that Ferriss is a pretty big guy (tall and muscular), so pushing a Chinese guy a few feet isn't that much of an accomplishment, even if you take into consideration he's trying to kick your teeth down your throat.
While doing a bit of web research on Ferriss to get some objective info on him, I found this hilarious post: 5 Time management tricks I learned from years of hating Tim Ferriss, with this great quote:
The week that Tim actually works a four-hour work week will be a cold week in hell. Tim got to where he is by being an insanely hard worker. I don't know anyone who worked harder at promoting a book than he did. But the thing is, he didn't call it work. Somehow, sliming me into having coffee with him to talk about his book is not work.
Fine. But then his four-hour work week is merely semantic. Because everything Tim does he turns into what the rest of us would call work, and he calls it not-work. For example, tango. If you want to be world-record holder, it's work. It's your job to be special at dancing the tango. That's your big goal that you're working toward. How you earn money is probably just a day job. So most weeks Tim probably has a 100-hour workweek. It's just that he's doing things he likes, so he lies to you and says he only works four hours. He defines work only as doing what you don't like.
Ferriss' other advice is to be difficult during interpersonal interactions if you aren't getting what you want. One of his examples is from college: if a professor gave him anything less than an A on the first paper or non-multiple-choice test, he'd show up at their office and winnow them down over three-hour sessions where he'd pepper them with questions and challenges so he could play to their biases, but also with the implied threat that if they didn't give him an A next time, he'd be back for another grueling session.
However, he says one of the ways you can gain efficiencies in business is to "fire" your difficult customers. He realized he was spending the majority of his time on the minority of his customers, so he told them take it or leave it but don't bug him anymore. All but one left, and the one who left more or less behaved himself after that.
Note the paradox, though, that Ferriss would "fire" himself as a customer.
Verdict: Most of Ferriss' advice is largely unworkable unless you want to work constantly and be somewhat of a hypocritical jerk (and hopefully have somewhat of a talent for self-promotion).