As popular uprisings spread across the Middle East, popular wisdom often held that the Gulf States would remain beyond the fray. In Sectarian Gulf, Toby Matthiesen paints a very different picture, offering the first assessment of the Arab Spring across the region. With first-hand accounts of events in Bahrain, Saudi Arabia, and Kuwait, Matthiesen tells the story of the early protests, and illuminates how the regimes quickly suppressed these movements. Pitting citizen against citizen, the regimes have warned of an increasing threat from the Shia population. Relations between the Gulf regimes and their Shia citizens have soured to levels as bad as 1979, following the Iranian revolution. Since the crackdown on protesters in Bahrain in mid-March 2011, the "Shia threat" has again become the catchall answer to demands for democratic reform and accountability. While this strategy has ensured regime survival in the short term, Matthiesen warns of the dire consequences this will have—for the social fabric of the Gulf States, for the rise of transnational Islamist networks, and for the future of the Middle East.