Introduction / Mathias Albert -- On the modern systems theory of society and IR. Contacts and disjunctures between different kinds of theorizing / Mathias Albert -- Politics, modern systems theory and the critical purpose of international relations theory / Thomas Diez -- "Corpus mysticum": Niklas Luhmann's evocation of world society /Stefan Rossbach -- The "English school" and world society / Chris Brown -- Sociological institutionalism and the empirical study of world society / George M. Thomas -- World society from the bottom up / Lothar Brock -- World society, systems theory and the classical sociology of modernity / Dietrich Jung -- Systems and sovereignty - a systems theoretical look at the transformation of sovereignty / Anders Esmark -- "World opinion" and the turn to post-sovereign international governance / Hans-Martin Jaeger -- Society's war: the evolution of a self-referential military system / Gorm Harste -- Organizations in/and world society: a theoretical prolegomenon / Mathias Albert and Lena Hilkermeier -- Governance in a world society: the perspective of systems theory / Dieter Kerwer -- Constructivism and international relations: an analysis of Luhmann's conceptualization of power / Stefano Guzzini -- Concluding remarks / Mathias Albert.