Published in London in 1651, immediately after the English Civil War, *Leviathan* is the masterpiece of Thomas Hobbes, who had spent much of the war in exile in Paris. Its method is openly declared: begin from assumptions about human nature, and reason out political obligation by something like geometric demonstration.

Hobbes' opening picture — the 'state of nature' — is one of the most powerful thought experiments in modern political theory. Remove all authority: human beings are roughly equal in ability, want the same scarce goods, and fear the uncertainty of the future. The result is war of all against all — *bellum omnium contra omnes* — in which life becomes 'solitary, poor, nasty, brutish, and short'. Hobbes is not claiming that violence is natural in some sentimental sense; he is claiming that *in the absence of a sovereign* violence is the rational expectation.

The escape is the social contract. Individuals, retaining only the right to preserve their own lives, transfer all other rights to an absolute sovereign — the sea-monster of the title — which may be a person or an assembly so long as its decisions are final. Divided sovereignty, for Hobbes, is a contradiction in terms, a recipe for sliding back into the war.

Hobbes' conclusions look authoritarian, but the underlying move is unmistakably modern: legitimacy flows from below, from contract, not from above. Locke and Rousseau fill the same 'state of nature / contract' frame with very different content. The deep irony is that, to defend absolute sovereignty, Hobbes had to invent the grammar of democratic thought. The book's frontispiece — a giant ruler composed of countless tiny human bodies — is the most famous attempt to picture that idea.