Iván Szelényi's Yale course Foundations of Modern Social Theory turns to Montesquieu, tracing his shift from the individualism of Hobbes and Locke toward a collectivist view of society governed by a general will above individual opinion. The lecture covers Montesquieu's historical context, the major themes of The Spirit of the Laws, his classification of governments, and his argument for separating executive, legislative, and judicial powers, the scheme the United States Constitution later followed. It closes with Montesquieu's claims about how climate and environment shape both individuals and social structure, ideas Szelényi treats as dated but historically significant as an early attempt to link environment and politics. Chapters are marked for each section, running from historical background through the separation of powers to environmental theory, giving a clear map of a wide-ranging lecture on Enlightenment political thought.