For starters, don't let my ratings give you the impression that I wouldn't recommend the book to someone. I think it is required reading. My issue with the author is that he is essentially misrepresenting the content of the book, which is itself all over the map and poorly organized.
(1) The title is not representative of the book. There is no secret here and it certainly won't lead to finding your Holy Grail. There is no secret that tells you what your trading system might be. There is nothing that facilitates a trader finding a good time frame or a good market. The book merely offers a laundry list of things to consider before launching off on a more focused investigation of one's trading personality and suitable models. There are far better books on these subjects, including risk and money management, that a trader should spend his or her money on.
(2) There is no original work here -- the principles on risk management have been practiced since the advent of modern market speculation. He tries to dispel what he thinks are misconceptions about risk and money management, but he ends up sounding petty. The important points he conveys could be explained without the unnecessary posturing.
(3) The author pans a good number of people who either write in the field or who have traded successfully or who have mentored other traders. Yet, the author does not trade himself. He uses his "research" to justify pet theories about markets and about trading, but by definition this game is not reducible to anything but banal generalizations. It is ultimately an individual game. I think his panning of others is disingenous and a little irritating. On top of that, I see no direct evidence of any real research coming out in the prose. This makes me very suspicious.
(4) He seems to think his writing is profound. In fact, any trader who gives some honest thought to this game and who knows a little arithmetic is going to come to similar realizations on his or her own -- but that won't necessarily keep one from failing or blowing an account or two. The tone of his writing leads me to believe that he truly wants to be regarded as an academic expert in the field, which I also find irritating. In fact, I think it detracts from the authority of the ideas he calls his own (but which in fact are not his own).
5) The beginning trader will find many of these ideas original and of course ascribe them to Van Tharp, which is what he has relied on to bolster his reputation and to generate business for his seminars and other course offerings. I don't have a problem with this, but I suspect that Tharp's success rate with his students is about on par with the general success rate of traders in the markets. I find no good reason to participate in any of these seminars until he can show me that a statistically significant portion of his students go on to "trade their way to financial freedom." I doubt that better than one in 20 achieve this kind of success. Feeling empowered with "new knowledge" does not guarantee trading success or justify the expense. Disciplined implementation of the basic ideas of TYWTFF are enough to achieve success.
6) He is now in the business of remixing -- like so many authors these days, some of whom are previous associates of Mr. Tharp (like Jack Schwager). Every book he has written after TYWTFF is simply a rehash of those ideas. There is nothing wrong with capitalizing on past success, but there is something sleezy about the way he is doing it and on top of that, just about everything that he has done seems unfinished, which tells me that he really isn't as meticulous in his research and his courses as he would want me to believe.
I suspect his son is doing no better in his trading than Van Tharp himself does. Don't be fooled by promises of becoming a "supertrader" as Tharp likes to insinuate. Stick to the simple principles he outlines and then investigate those principles more deeply with other authors.
It is unfortunate that this book is as popular as it is -- there are so many good books out there that offer so much more and without all the personal affectations in the writing. The author owes us a complete revision that is more concise and better organized -- and without all the silly footnotes.
This would never have passed for a dissertation where I went to school, yet he makes sure we know he has a PhD. These days that credential confers little authority -- and in trading it is practically irrelevant. That said, I would still recommend TYWTFF as an important book. If a new trader sticks to the simple concepts on position sizing alone, the value of the book is worth much more than the jacket price.