Personally, I think a good book for personal development is not only one that gives you the strings to be happy, but especially one that makes you want to take action. If like me you have already read several books on personal development, then you know that often the advice is very similar. But one day the magic happens between the player and a particular book. A slightly different way of saying things, a new angle of attack, or it is simply THE right time in his life to hear and digest the message.
In my case, I needed to hear the message as fable, more digestible. From a pragmatic nature, I also need a true method, not just principles. In that, this book speaks to me perfectly, although I understand that it can not cause anything from others.
The impact of this book on my life is undeniable and I can highly recommend it. If it did not cause anything to you, then keep searching THE book that will tell you. The game is well worth the effort.