Hedley Bull

In 1977, Bull published his main work, The Anarchical Society. It is widely regarded as a key textbook in the field of international relations and is also seen as the central text in the so-called "English School" of international relations. In this book, he argues that despite the anarchical character of the international arena, it is characterised by the formation of not only a system of states, but a society of states. His requirements for an entity to be called a state are that it must claim sovereignty over (i) a group of people (ii) a defined territory, and that it must have a government. States form a system when they have a sufficient degree of interaction, and impact on each other's decisions, so as they "behave—at least in some measure—as parts of a whole." A system of states can exist without it also being a society of states. A society of states comes into existence "when a group of states, conscious of certain common interests and common values, form a society in the sense that they conceive themselves to be bound by a common set of rules in their relations with one another, and share in the working of common institutions."

In 1965, Bull was appointed director of the Arms Control and Disarmament Unit of the British Foreign Office, forfeiting his Australian identity for British citizenship. Two years later, in 1967, he was appointed to a professorship of international relations at the Australian National University (ANU) in Canberra.

Bull was born in Sydney, Australia, where he attended Fort Street High School. He went on to study history and philosophy at the University of Sydney, where he was strongly influenced by the philosopher John Anderson. In 1953, Bull left Australia to study politics at Oxford, and after two years he was appointed to an assistant lectureship in international relations at the London School of Economics and Political Science (LSE).

Hedley Norman Bull FBA (10 June 1932 – 18 May 1985) was Professor of International Relations at the Australian National University, the London School of Economics and the University of Oxford until his death from cancer in 1985. He was Montague Burton Professor of International Relations at Oxford from 1977 to 1985, and died there.