This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book presents the main definitions and classifications of knowledge intensive business services (KIBS) firms and of the related industries. It describes the main categories of innovation in KIBS, distinguishing between product, process, concept, technological, organizational and interface innovations. The book explains how new information and communication technologies help KIBS firms to increase their level of internationalization. New technologies allow many traditional barriers of service replicability and exportability in foreign markets to be overcome. The book focuses on modularity in software and websites, which are undergoing a profound architectural change and today are converging overall toward a modular structure. KIBS and service literature published over many years suggests that these properties negatively affect the impact of innovation on KIBS firms’ productivity and growth.