This book addresses the foundations of economic growth at the firm level, combining both theoretical and econometric contributions by established scholars. Challenging ideas revisit Marshall's view on the management of innovation, investigate the decision of firms to venture into entrepreneurship and clarify some misunderstanding about Schumpeter's views. The book goes on to shed light on the classical specialisation-flexibility trade-off and provides a vision on the role of the knowledge-based economy and firm networks on technology development. Firm survival and performance, price-cost margins and the determinants of research intensity are also investigated econometrically. This book will be of great relevance to students and the academics involved in research projects that address issues of firm growth, behaviour and performance. It will also appeal to practitioners seeking tangible results concerning the relationship between key economic variables at the firm level, and to policymakers who need to be aware of the impact that changes in the organization of industries and markets may have on the performance of firms.