The Spirit of the Laws – Montesquieu

"Power should be a check to power."

Montesquieu undertakes a comparative study of three types of government: republic, monarchy, and despotism. He formulates the theory of the separation of powers—dividing the state into legislative, executive, and judicial branches—to prevent tyranny and protect political liberty.

This massive work is one of the most influential political texts in history. Its ideas formed the basis of the American Constitution and the democracies of modern Europe. It is a foundational text of liberal political theory and constitutional law.