First, the good news. As someone relatively new to the world of running, this book did increase my understanding of various aspects of running. Now the bad news. This book has some of the sloppiest editing I have seen in a while. To name a few... when explaining how the joints work in the body, the text referred to a helpful visual that was unhelpfully absent from the book. In another section it uses tables of figures and asks the reader to refer to certain colored columns, only the tables were all in shades of grey! That oversight impacted the reader's ability to understand the test considerably. Beyond the distracting editing issues, I found some of the arguments to be poorly supported. The arguments were made in the name of science, but presented with little supporting evidence. I might not have a degree in physiology, but I certainly can sniff out a poorly researched argument. I was amused at the negative light the authors cast on chi running, yet never really explaining what they thought was wrong with it. In fact, they ended up agreeing with the main principles of it, but cast that aside stating that it could be dangerous for a seasoned runner to make a major change in their running style! I can't help but wonder if they are just confused or are walking the fine line between writing substance and keeping the Runner's World advertisers happy.