This book provides vital theoretical underpinnings for the emerging 'neo-structuralist' reading of macroeconomics based on the heterogeneous accumulation behaviour of public and private sectors. The work of Kalecki is used to build up a rigorous analysis of the semi-industrial economy which is not only suitable for practical policy formation but also marks a breakthrough in modern development economics. The topics covered include: the microeconomic roots of macroeconomic behaviour; stabilization, employment and growth policies in a mixed economy; and the problems of sectoral balance and market management in the planned economy.