The regime in Tehran, traditionally ruled by the Shia clergy, is transforming into a military dictatorship dominated by the officers of the Islamic Revolutionary Guards Corps (IRGC). The rise of the IRGC is bound to challenge the interests of the United States in the Middle East and beyond. The author uses rarely studied sources from the Persian-language press to reveal how the IRGC officers have risen to power in Iran and the impact of the Islamic Republic's transformation into a military dictatorship. He highlights how Iran's recent attacks against American diplomats and support for armed insurgents in Iraq and Afghanistan indicate the IRGC's increasing adventurism and risk taking.