Per Nilsen is a professor of social medicine and public health, with a particular focus on implementation science, at Linköping University, Sweden. He was responsible for building a research programme on implementation science at Linköping University. He leads several projects on implementation of changes in health and welfare, including alcohol prevention. Nilsen has developed Master and doctoral-level implementation courses, which have run annually since 2011. The PhD course attracts students from the Nordic countries and beyond. Nilsen takes particular interest in issues concerning practice change and the use of theories, models and frameworks for improved understanding and explanation of implementation challenges.