On the occasion of the 20th anniversary of PROFIBUS, PI (PROFIBUS & PROFINET International) is issuing an anniversary book describing the background and history of PROFIBUS. In addition to accounts from contemporary witnesses, companions, and technological heads, the founders of the RPAs (Regional PI Associations) also report on their experiences with PROFIBUS on the international stage. From the descriptions it is clear that PROFIBUS is more than just a technology. Rather it was greatly influenced by the people who worked hard on its development, quality assurance, and marketing. The anniversary book presents, for example, why the founders had already internalized the idea behind the Web 2.0 technology and had brought it to life in the committees, where the groundbreaking idea of an open communication concept came from, why China was responsible for the breakthrough of PROFIBUS technology in Japan, and why a defective fax machine could have decided the fate of PROFIBUS. In addition, the volume includes many more stories about technologies, such as PROFIdrive, PROFIsafe, and PROFINET. Completing the volume is an outlook of where the future technological journey of PI will lead. The key developments here are PROFIenergy, IO-Link, and innovative engineering and diagnostic concepts.The anniversary book is available in German and English.