This text is highly recommended for managers and serious students of quality. Major US companies issue this reference and training manual to all managers during their quality training. This volume is also very valuable as a stand-alone reference on using statistics with a business and quality perspective.
This book was used in conjunction with a statistical class. I wouldn't go it alone on this without a professors guidance. If you wanted to learn it on your own, I don't think the explanations with the formulas are enough.