This document discusses contribution margin analysis, which analyzes the profitability of various parts of a business like customers, products, and sales areas. It provides an example of a company that used contribution margin analysis to categorize its customers into four groups - solid citizens, attractive demanders, players, and risky losers - and was able to improve profitability by focusing more on the solid citizens and less on the risky losers. The document recommends that all businesses use contribution margin analysis to help make better strategic and tactical decisions.