Japanese semiconductor firms are well known for obtaining dynamics in a short period of time and achieving even global leadership. A significant portion of their success are attributable to cooperative interfirm relations and the development of intermediate organizational structure based on long-term relationship between firms. The purpose of this book is to explain how interfirm relations contributed to their dynamics during the golden age of the semiconductor industry. Meanwhile this book clarifies the real source of dynamics in interfirm relations and how the firms have interacted. The author concludes that the competitive-cum-cooperative (CCC) interfirm interaction are observed. Quantitative and qualitative findings show that firms enjoy not only flexible cooperation based synergy effects, but also dynamics market-like effects by creating competition among partners through CCC interaction.