The connection between profit and economic theory is an intimate one. Economic analysis, in very large part, developed only with the maturing of a capitalist system in which production activities became overwhelmingly organised on the basis of profitability. Moreover, the attempt to understand such a system has been the focal point of economic interest ever since. However, a generally accepted theory of profit has not emerged at any stage in the history of economics. The current state of affairs is no exception to this. Various concepts of profit and of the ‘profit system’ abound, different strands of analysis show few signs of convergence and theoretical controversies remain intense.