Pierre A. Clavien, a world-renowned surgeon-scientist, is currently professor of Surgery and Transplantation at the university of in Zurich, Switzerland. After a Swiss board of surgery in 1989, he moved to Toronto, Canada, to complete a PhD program in organ preservation, followed by a clinical fellowship in HPB surgery and liver transplantation. He then moved to Duke University Medical Center, Durham, NC, where he initially led the liver transplantation and HPB programs, and subsequently the Division of Transplantation, and obtained the rank of full Professor within 4 years. The main interest of Prof. Clavien has been in several aspects of transplantation and liver surgery. Since 1994, he has run an active basic science laboratory continuously funded through NIH and Swiss National Science Foundation Grants and other private and non-private sources. His areas of research include organ preservation, liver ischemia-reperfusion injury and liver regeneration, and pathogenesis of cancer, as well as outcome research with publication in Science, Nature, PNAS, Annals of Surgery, Gastroenterology, Lancet and NEJM. His laboratory made the discovery of serotonin as a key mediator of liver regeneration and pathogenesis of cancer (Science 2006). Prof. Clavien has also developed a simple and widely used system to evaluate complications after surgery, which holds his name.Prof. Clavien received the honorary fellowship of the American College of Surgeons (ACS) and of the American Surgical Association (ASA). He was also appointed honorary member of the Académie Nationale de Médecine in France and in year 2020 he became member of prestigious National Academy of Medicine USA, as being the only surgeon outside of the USA.