The turbulent history of modern Iran begins with the fall the Qajar dynasty's traditional polity in 1925, followed by the westernizing policies of Reza Shah and Muhammad Reza Shah, who ruled until the Islamic revolution in 1979. The revolution introduced a new ruler, Ayatollah Khomeini, who created an Islamic republic that was a hybrid of tradition and modernity.

The Qajar Shahs had ruled autocratically in a traditional Iran where due process of law was unknown and punishment was swift, involving physical torment and at times violent death. Hardly anyone was sentenced to prison. Torture was a part of the process by which the guilt of the accused was established. With the arrival of European-style "modernity," the Pahlavi dynasty adopted new policies. Reza Shah, who ruled from 1926 to 1941, created a centralized administration, a standing army, a police force for cities, and a gendarmerie for the countryside. In the absence of...