The purpose of the paper is to draw attention to one of the sharpest expressions of the cleavage of attitudes between economists and businessmen, and to advance some tentative suggestions for improvements in both analysis and application. This relates to the use by business of a method of cost-volume-profit analysis, and of pricing and volume adjustments, which is referred to as break-even analysis and which, prima fade, ignores the economists' generalized theorems of cost and revenue behavior. The arguments which the paper has developed, however, set a program of research and development by the cost accountant, and suggest that economists now give their attention to examining the shape and stability of aggregate revenue and cost functions over time and over output ranges, applying their resources of statistical analysis to the reconstruction of empirical microfunctions and variables. For the financial manager in industry, the lesson of the analysis is that he cannot rely with the same degree of confidence on the more naive forms of his break-even charts.