Dr. Simon Rüegg is a veterinary epidemiologist at the University of Zürich, Switzerland. He works towards a more respectful approach to animals, people and the environment. After graduating as a veterinarian, he worked on wildlife diseases in Mongolia and then created his own practice for exotic pets in Switzerland. Since he returned to research, he studies how to make things work in complex systems. He acts as a systems practitioner in health, disruptive thinker and facilitates knowledge integration, particularly in the One Health domain. His ambition is to create tools for health practitioners to help conceptualize and navigate in complex adaptive systems. For example, he led an interdisciplinary working group to develop a framework to evaluate One Health in the frame of the “Network for Evaluation of One Health” funded by the European Cooperation on Science and Technology (COST, TD1404). The framework was validated with case studies and was published open access (handbook: https://doi.org/10.3920/978-90-8686-875-9; case studies: https://www.frontiersin.org/research-topics/5479/). This process revealed several challenges at conceptual as well as methodological level. Some of those will also be relevant to implement One Health in practice, such as the need to balance between imposing health norms and relying on participation to tackle complex health challenges, overcoming the scission between the two narratives of benefits from nature and threats from nature, and the need for a scalable definition of health. With his research he is looking for answers. The CoEval-AMR project (https://guidance.fp7-risksur.eu/) produces guidance for the evaluation of integrated surveillance of antimicrobial use and resistance. His PhD students introduced a One Health approach to brucellosis control in Kazakhstan and the human-non-human primate conflict in Thailand. He contributed to COHESIVE (www.ohras.eu), an initiative to establish integrated national zoonosis platforms for sharing surveillance data and their interpretation across Europe. Currently, he contributes to a project evaluating the operationalision of one health units in Guinea and the Democratic Republic of Congo. He also is member of the WHO One Health technical advisory group, member of the WOAH ad hoc group on reducing the risk of disease spill over events at the markets selling wildlife and along the wildlife supply chain, member of the EFSA One Health Surveillance working group, founding member of the European chapter of Ecohealth International: Network for Ecohealth, and chair of the Swiss Association of Zoo, Wildlife and Exotic Pet Veterinarians.