Functional differentiation has long been at the heart of sociological thought, and as such has become a defining feature in the evolution of modern society; one which distinguishes it from pre-modern societies which have instead typically differentiated by means of segmentation, or stratified social systems such as class. Drawing on the latest developments on differentiation theory in international relations and sociology, this book brings together contributions from leading IR scholars and sociological theorists to offer a unique interdisciplinary synthesis in which contemporary world...