This text exemplifies how to synthesize new control thinking with an understanding of process variability, to diagnose abnormalities and their causes in aluminum producing plants. Most examples also demonstrate the need for different human behavior and a more scientific, questioning approach to the management of production. This approach is drawn from the authors' more than 25 years of experience, not only in metals plants but also in oil and gas production and food processing plants. Readers get a view into the human aspect of accidents and the problems of production.