Hans Brintzinger is Professor of Chemistry at the University of Konstanz, Germany. In his lecture, entitled "Twenty Years of ansa-Metallocene Polymerization Catalysis. Where are we Standing Now?", he first reviewed the milestones in his and other colleagues' research on ansa metallocene catalysts and then focused on current mechanistic aspects, challenges, and problems awaiting solutions. Hans Brintzinger's work is dedicated to ansa-metallocenes. He introduced this new class of organometallic compounds, thus laying the foundation to the development of a very active and very selective new catalyst family for olefin polymerisation. The FECS Lecture serves to enhance the image of European chemistry and to promote scientific cooperation in Europe. It rotates among FECS member societies and is delivered at a scientific event outside the lecturer’s own country. The FECHEM Conference on Organometallic Chemistry is one of a series of FECS sponsored scientific conferences and is organised by the FECS Division of Organometallic Chemistry. The Zürich event brought together chemists from industry and academia and provided an international forum for the presentation and discussion of new findings in the dynamic and exciting field of organometallic chemistry. 450 scientists from 39 countries worldwide participated.