This chapter will present input-output preliminaries to the multi­ sectoral linear programming models discussed in the subsequent chapters. Leaving its rigorous mathematical formulation to the next chapter, we shall in the present chapter limit our input-output analysis to the fundamental assumptions, variables, and relations involved. Specifically this chapter will deal with: (a) the structure of input-output relations, and (b) the endogenous net capitalformation sector. The first of these section will be found to involve a static Leontief input-output model, while the second section will be found to indicate the possibility of integrating the Leontief approach and the post-Keynesian growth theory involving explicit linear relations and implicit optimands.