This book studies the dynamics of alliance group formation in technology-based networks. The author attempts to develop the concept of alliance blocks from a social network perspective, and explores the relationship between alliance block membership and innovative performance in a changing technological environment. The book demonstrates that as an alliance network grows, the likelihood of alliance block formation also increases. The author presents evidence that pursuing a block membership strategy favourably affects innovative performance. This is true for conditions of both cumulative and disruptive technological change. However, over time the technology profiles of alliance block members tend to become more similar, which can eventually lead to a reduction in innovative activity. She also reveals that, when compared to their non-member counterparts, firms in alliance blocks are likely to apply for more patents, hold more central positions in the network, have larger revenues and undertake more R&D intensive research. In addition, they are also inclined to originate from an Asian background. This is the first book to propose a well-developed theoretical framework, supported by empirical evidence, to explain alliance block formation processes and their effect on innovative performance. As such, it fills a substantial gap in the literature on competitive rivalry among alliances, an increasingly important area of research. It will be essential reading for academics and practitioners in the fields of industrial organization, strategic management, technological alliances, competition and innovation studies.