Obituary for Ruedi Müller-Wenk Ruedi Müller-Wenk was a lecturer and associate professor at the HSG. He was considered a pioneer in life cycle assessment and taught environmental technology and life cycle assessment at the HSG. In his scientific work, he combined both economic and ecological reasoning. An obituary written by Thomas Dyllick, Delegate for Sustainability Management at the HSG and Dr. Arthur Braunschweig, Presiden of the "Union for Sustainable Economy (öbu)". 19 December 2019. Nowadays, when food health receives an award based on a “Nutri” score, a kind of traffic light system, or when the EU proposes to assess the sustainability of investments using an overarching scoring guide, extensive scientific groundwork is required here to develop the sophisticated assessment concepts needed. For a long time, this work was referred to as “life cycle assessment” or “ecological accounting”, in the development of which Ruedi Müller-Wenk played a significant role. Müller-Wenk was a lecturer and associate professor at the HSG. He was a pioneer when it comes to life cycle assessment and taught environmental technology and life cycle assessment at the HSG. Integrating environmental considerations into business processes Müller-Wenk was a calm and precise, interested, pragmatic and very independent person. He crossed the border between “feeling” and “counting”: It was clear to him that it was not possible to count the really important things in life, but that figures were indispensable for the management of larger organisations. Forty years ago, the equal coexistence of economy and environment was already a deep concern for him. He realised that environmental concerns always received the short end of the stick when it came to business-related decision-making processes, due to a lack of quantifiability. He therefore decided to develop such an environmental quantification system himself. Müller-Wenk was a full-time technical director back then at the well-known Rorschach-based food processing company, "Frisco", formerly known as "Roco" (Rorschach Conserven). Using this company as an example, he developed the concept of ecological accounting. With this publication from 1978, Müller-Wenk was one of the fathers of life cycle assessment, as it is well known today. What was unusual about his approach was that from the very beginning he considered it necessary to make an assessment using a uniform evaluation system, which was able to provide a common denominator for the wide variety of environmental impacts that was analogous to money in the economic sphere. His pioneering achievement here was that he actually developed such an evaluation system himself. Life cycle assessment of the Federal Office for the Environment This concept was developed later with his active participation into an independent Swiss evaluation concept for life cycle assessments, which was based on environmental pollution points that are now published by the Federal Office for the Environment and regularly updated. In Switzerland, his approach was quickly adopted by Migros, Coop and other companies for the purpose of ecological optimisation. Internationally however, such as in the International Organization for Standardization (ISO), his approach remained frowned upon for almost 30 years, until recently the EU began to develop its own scoring system. After his retirement, Müller-Wenk developed further methodological approaches at the HSG Institute for Economics and Ecology (IWÖ-HSG) together with PhD students from the HSG and ETH Zurich, within the scope of interdisciplinary projects of the Swiss National Science Foundation, the German Federal Environmental Agency and the EU, which were widely regarded as impossible, such as the consideration of traffic noise or land use in life cycle assessments. Müller-Wenk worked carefully, and he often thought along non-typical lines. It was important to him, in his industrial and university work as well as in his private life, to be in close contact with the real world. During discussions he was able to link little things and big topics, everyday things and special things in an unexpected way and draw interesting conclusions from them. He was persistent in the way he worked and was only satisfied when he had found a conclusive solution. Training of managers who think in a sustainable way Müller-Wenk taught economics and environmental studies at the HSG and supervised doctoral students at the HSG and ETH Zurich. Functioning multidisciplinarity was very important to him, because the research questions, which needed to be solved, demanded this. And right from the start, he was concerned with effectively linking the economy and the environment as well as economic and ecological reasoning. He pursued this in a way which was very unique – by combining a leadership role in industry with his scientific activities. And those who took part in the exciting and often challenging rounds of discussions while enjoying a coffee at the IWÖ-HSG not only received sound instruction, but also profound enrichment. Müller-Wenk passed away on 13 November 2019. He, together with his wife Esther who has already passed away, leave behind four children.