First published in 1977, this classic work is foundational to the “English School” of international relations. Bull’s central thesis is that while the international system lacks a higher authority—making it “anarchical”—it is not devoid of order. Instead, states form a “society” by adhering to common rules, norms, and institutions that regulate their interactions. Bull explores how order emerges from this apparent anarchy, examining the historical evolution of the state system from the Peace of Westphalia and the development of concepts like sovereignty and non-intervention. He argues that states, despite their pursuit of self-interest, recognize shared interests and values, which lead to the creation of institutions such as diplomacy, international law, and the balance of power.

Bull delves deeply into the mechanisms that sustain international order. He discusses the role of great powers, the causes and consequences of war, and the function of institutions like just war theory and collective security. According to Bull, these institutions and practices do not eliminate conflict but help manage it, allowing for cooperation and predictability even in the absence of a global enforcer. He emphasizes that the balance between anarchy and order is delicate, shaped by the ongoing tension between forces that pull states apart and those that bring them together.

The book’s enduring influence lies in its nuanced analysis of how international society operates. Bull’s work encourages readers to see beyond the binary of chaos and order, highlighting the ways in which states, through mutual recognition and shared norms, construct a workable—if imperfect—system of coexistence. His insights remain relevant for understanding contemporary issues like sovereignty, intervention, and the challenges of global governance.