This chapter explains the nature of the economic problems and conceptions with which Cost Accounting and economics, each in its own separate way, the gain which would result to each of these subjects from a fuller co-operation between them and the lasting and cumulative benefit which the community would be almost certain to achieve from the co-operation between the Cost Accountant and the economist. Now modern economic theory teaches us that if we are to understand the causes which regulate value it is to this margin that must go in order to watch the play of the forces which govern value. Resources are better devoted to large or small concerns in an industry, can at present only be answered deductively or by trusting implicitly in inferences drawn from the actual tendencies. In order to determine the price to be declared for individual products the Government authorities had to work out the quantity of each product, which it estimated was required.