The Social Contract, Or Principles of Political Right (1762) by Jean-Jacques Rousseau, is the book in which Rousseau theorized about social contracts.

Rousseau expounded the belief that the ideal society is one in which a man's contract was between himself and his fellow men, not between him and a government. Like John Locke, Rousseau believed that a government can only be legitimate if it has been sanctioned by the people, in the role of the sovereign.

Rousseau claimed that a perfect society would be controlled by the "general will" of its populace. While he does not define exactly how this should be accomplished (as there are many possible ways, each suited to different situations), he suggests that assemblies be held in which the every citizen can assist in determining the general will. Without this input from the people, there can be no legitimate government. Importantly, this input cannot come from representatives, but must be from the people themselves.

The Social Contract was a progressive work that helped inspire political reforms or revolutions in Europe, especially in France. The Social Contract finally expelled the myth that the King was appointed by God to legislate; as Rousseau asserts, only the people, in the form of the sovereign, have that all powerful right.

The heart of the idea of the social contract may be stated simply: Each of us places his person and authority under the supreme direction of the general will, and the group receives each individual as an indivisible part of the whole...