Polyolefins (POs) constitute an extremely interesting family of materials. They include large-volume materials such as polyethylene and polypropylene and specialty materials. Outstanding scientific and technology developments have led to the most aggressive, endless, always increasing, successful growth speed of any family of large-volume materials. For those of us who have lived through the entire PO adventure, from its problematic beginnings to the eventual successful developments of the last 25 years, it has been a quite unforeseeable and unexpected story not shared by the majority. The main reason for such behavior and the present situation is the inherent complexity of their catalytic systems, which are difficult to understand and manage, along with all the consequences in terms of the process versatility, the reliability and cost, the lack of product properties, and the possibility of new material creation and commercial availability. After the early commercial disappointments of the 1960s and early 1970s, the deep commitment of the industry in research and development, mostly aimed at an understanding of the catalysis and its improvement and management, created the basis for and led to the generation of new, elegant, and versatile processes and, most importantly, to the generation of new products and properties. It activated that dynamic and aggressive growth that, since the late 1970s, has characterized the entire PO market and still, at the beginning of the third millennium, is not showing any sign of decline. An attempt to provide a rational explanation for such a unique case of technological and commercial success in the history of materials has led us to the following conclusions. First, dramatic improvements in the polymer properties and the generation of new materials have been the key reasons for their commercial success and continuous market expansion. Second, the tremendous and dynamic development of new, elegant, and versatile technologies has been and is the fundamental prerequisite for the generation of that rich world of new properties and materials. Third, the strategic management of the technological background and potential for the creation of new properties and new applications has been and is the basis for the fast and successful market expansion. The key technological driving force has been the understanding and management of the catalytic system. The early generations of chromium-based and Ziegler-Natta catalysts, after a difficult beginning, have progressively accelerated in their development toward new revolutionary generations with outstanding potential in terms of the creation of new polymer properties. The most recent families of single-site catalysts, together with the still largely unexploited potential of the previous Ziegler-Natta, chromium, and vanadium catalysts, are showing the ability to guarantee the continued support and fueling of the expansion for several further decades. The development philosophy will always be more tuned toward the creation of low-cost, low-environmental-impact polymers and processes, with a minimum amount of constraints. Today, at the beginning of the new century, we see the PO future as still very bright because of the huge, unexploited potential of already existing and emerging technologies. The PO adventure continues and is still exciting like it was 50 years ago. (C) 2003 Wiley Periodicals, Inc.