The author completely disregarded the fact of playing to your strengths, personality types and how some jobs and trades may be better suited to the end-user than others. There's more to it than just putting in the hours and getting good at what you do. In summary, I would advise everyone to read this book. It gives you insights that can alter the trajectory of your life in a positive way. But please consider doing something you have a an interest in as you'll end up with nothing to lose. Being good at something valuable that you also have a deep interest in. Don't rely on "developing that passion" once you're really good as it simply is not guruanteed!