At the heart of the Middle East, with its regional conflicts and proxy wars, is a 1400-year-old schism between Sunni and Shia. To understand this divide and its modern resonances, we need to revisit its origins, which go back to the death of the Prophet Muhammad in 632, the accidental coup that set aside the claims of his cousin and son-in-law Ali, and the slaughter of Ali's own son Husayn at Kerbala. These events, known to every Muslim, have created a slender faultline in the Middle East. The House Divided follows these narratives from the first Sunni and Shia caliphates, through the medieval caliphates and empires of the Arabs, Persians and Ottomans, to the contemporary Middle East. It shows how a complex range of identities and rivalries - religious, ethnic and national - have shaped the region, jolted by the seismic shift of the Iranian Revolution of 1979. Rogerson's original approach takes the modern chessboard of nation states and looks at each through its particular history of empires and occupiers, minorities and resources, sheikhs and imams. The result is a book of wide-ranging empathy, understanding and insights.