For those of you who do not know, Dalio previously published his "Principles" as a ~100 page article online for free, however removed it to begin selling this book. After reading both, I think this book provides an excellent extension to the original however at the cost of nearly 5x the reading time required. If you are not an avid follower of Dalio and Bridgewater, I would recommend finding a PDF of his earlier version online and if that does not suffice then consider purchasing this. Also, if you watch his frequent talks (can be found on YouTube), you will already know a lot about his personal history and the history of Bridgewater as covered in the beginning of this book. That said, Dalio is a legend in the HF world and I found it well worth the extra $18 to learn a little more from one of the smartest men alive.