I stumbled across this book about 10 years ago in a trade publication. At that time craft training was imperiled by the decline of the trade unions in our area and I was searching for a tool to help bolster training for young and inexperienced employees. I strongly disagree with the previous review that states this book is very boring. Over the last ten years I have bought about 30 copies of the book. Basic math principles as they apply to the pipefitting trade are laid out very well and easy to understand. Also, the author does a really good job of laying out step by step, the proper way to use a scientific calculator when working trade math formulas.