The purpose of this study is in keeping with the shift in concern over the eco­ nomic problems of growth to those of income distribution in recent years. Income distribution problems may be analyzed by not only the traditional procedures, but also by some extensions of the input-output technique as I shall demonstrate in this volume of the Lecture Notes. Some fruitful results are obtained by applying the extended input-output technique to income analysis as well as to output analysis. This volume consists of three parts. These parts may be viewed along two veins, with some overlapping unavoidable: (1) Parts One and Two contain extensions of the input-output analysis and (2) Parts One and Three contain studies of the effects of the structure of income distribution on some other economic relationships. First, as an extension of the input-output analysis, we present a synthesis of the Leontief interindustry matrix multiplier and the Keynesian income multiplier in disaggregated form, and introduce a new concept which may be called the "Interrela­ tional Income Multiplier" as a matrix. It is designed to analyze the interrelation­ ships among various income-groups in the process of income formation through the medium of industrial production activity. Although this multi-sector multiplier follows from Leontief's interindustry matrix multiplier, it is formulated by the inclusion of the income generation process, which is omitted in the usual input­ output open model, and by projecting the multiplier process into not only the output­ determination side, but also into the income-determination side.