Comprising more than 80 influential papers published in the 20th century, this set is the most comprehensive guide to appear to date. It is an indispensible research tool for students in upper level undergraduate programmes and taught postgraduate students. Researchers will also find it invaluable to have key essays in the development of international relations theory brought together in these volumes. The set gathers together essential papers from recent years, alongside classic studies from earlier periods. Organised into ten main areas, the themes covered include: * the nature and purpose of international theory * realism and idealism * scientific approaches * approaches to international cooperation * the liberal democratic peace * Marxism * historical sociology * critical theory * political theory and International Relations * normative approaches to world order A substantial new index and Linklater's new introduction make this an invaluable research tool.