This text seeks to provide an empirical and theoretical analysis of a distinct form of inter-firm collaboration in research and development (R&D): research joint ventures (RJVs). Of all types of co-operation, RJVs have received the most attention in both formal industrial organization and science and technology policy literature. The emerging theoretical economic literature on incentives of firms to join RJVs has not been followed by much empirical work. The volume attempts to fill a void caused by this lack of consistent data on the rate of RJV formation, RJV characteristics, and RJV member characteristics. Significant attention is paid to the role of RJVs in facilitating "virtual" firm diversification as necessary to pursue particular technological objectives. An effort is also made to blend the reported theoretical and empirical analyses with conceptual models of the process of technological innovation and models of industrial evolution in order to provide answers beyond the reach of the received economic theory. The book should be of interest to academic economists, policy makers, and business representatives. The microeconomic issues the book deals with overlap significantly with the interests of decision makers both in government and business.