The 1400-year old schism between Sunnis and Shi'is is as destructive a force now as it ever has been. This historical conflict is currently expressed by the struggle between Saudi Arabia and Iran--with no end in sight. But how did this conflict begin? The key to understanding the Arab world today is unlocking its past. In this authoritative account, John McHugo leads the reader through the history and development of present day Islamism, focusing on the critical moments. Charting the history of Islam from the death of the Prophet Mohammed to the present day, McHugo describes the conflicts that raged over the succession to the Prophet, how Sunnism and Shi'ism evolved as different sects during the Abbasid caliphate, and how the rivalry between the Sunni Ottomans and Shi'i'i Safavids ensured that the split would continue into the modern age. It is this centuries-old divide that has resulted in violence across the Arab world and other Muslim countries today. Definitive, insightful, and accessible, A Concise History of Sunnis and Shi'is is an essential guide to understanding the genesis, development, and manipulation of the schism that has come to define Islam and the Muslim world.