This volume summarizes the contributions presented at the 9th German-Korean Symposium on Comparative Administrative Law 2019. The symposium, which took place on 24 June 2019 in Mainz, aimed to analyze and discuss questions of new development trends in police law for both countries on a comparative basis. The event was under the academic direction of Prof. Dr. Josef Ruthig, Johannes Gutenberg University Mainz, and Uni. Prof. Dr. Dr. Jong Hyun Seok, Dankook University.