In over four decades of scientific exploration, Otmar Höll has approached international security from often unorthodox and unconventional perspectives. Starting with the issues of development and environmental policy, the challenge of a more comprehensive notion of security increasingly becomes a primary focus. Otmar Höll accepted this challenge and sought to combine it with his interests in the theory of political psychology, the practice of psychotherapeutic and mediated approaches to conflict resolution. Comprehensive Security therefore became a concept with a particular personal relevance. This Festschrift highlights Otmar Höll’s professional achievement through the contributions of friends, companions and colleagues.