This article provides an overview of recent progress in the theory of market structure, of the role of market leaders and the scope of industrial policy, presents new results through simple examples of quantity competition, price competition and competition for the market and develops new...

I develop a Schumpeterian model where the engine of growth is in the microeconomic structure of the patent races and derive new results on the determinants of growth. Under decreasing marginal productivity in the R&D sector, the equilibrium is characterized by small firms investing too little...