PART I: CONCEPTUAL OVERVIEW Introduction: Systems Theorizing in IR; M.Albert & L-E.Cederman Systems Theory beyond Explaining and Understanding; O.Kessler & F.Kratochwil PART II: 'MODERN' SYSTEMS THEORY Modern Systems Theory and World Politics; M.Albert Modern Systems Theory and/as Historical Discourse Analysis; H-M.Jaeger PART III: PROCESS-THEORETICAL APPROACHES Relationism and New Systems Theory; D.Nexon Complexity and Change in World Politics; L-E.Cederman Understanding System Dynamics; B.F.Braumoeller PART IV: ANALYSES OF MACROHISTORICAL PROCESSES English School as New Systems Theory; B.Buzan Differention, Rationalization and Actorhood; G.M.Thomas War and the Global Spread of the Nation-State; A.Wimmer & B.Min PART V: FINAL REFLECTIONS AND OUTLOOK Flatland: Quantum Mind and International System; A.Wendt