The famous philosopher responsible for developing the concept of the social contract was Jean-Jacques Rousseau. In his influential work, "The Social Contract" (1762), Rousseau argued that legitimate political authority is derived from a social contract agreed upon by individuals to form a collective society. This concept challenged existing notions of monarchy and divine right by proposing that governance should reflect the general will of the people. Rousseau's ideas greatly influenced the Enlightenment and modern democratic theory, emphasizing individual freedom and equality within the framework of a community, shaping political thought and practices, including the French Revolution.