This introduction relates the principal idea behind the book - that knowledge integration is a vital part of the dynamics of the innovation process to previous literature on knowledge integration, with its focus on companies' 'routine' activities. It presents the book's main empirical focus: internationally competing technology-based firms in, for example, the automotive, heavy electrical equipment, packaging machinery, telecom, tooling, and aerospace industries. It also introduces three major trends that affect conditions for innovation and knowledge integration: internationalization of R&D and production, transformation of markets, and changes in the character of developments in science and technology. In contrast to most definitions, the introduction emphasizes that knowledge integration is more than combining, sharing, or transferring different knowledge bases; it is also a process of creating new knowledge. The introduction concludes with an overview of the twelve chapters, describing how they provide an understanding of knowledge integration as a multilevel process.