International Relations Theory for the 21st Century is the first comprehensive textbook to provide an overview of all the most important theories within international relations. Written by an international team of experts in the field, the book covers both traditional approaches, such as realism and liberal internationalism, as well as new developments such as constructivism, poststructuralism and postcolonialism. Key subjects covered include: the clash of 'isms': a great debate? liberal internationalism realism Marxism critical theory constructivism the 'English school' of IR theory poststructuralism feminism postcolonial theory theories of state formation international political theory the future of IR theory