During his lifetime in the sixth and seventh centuries, the Prophet Muhammad built the foundations of what would become the second-largest religion in the world. This comprehensive guide presents the history of Islam, beginning with the agrarian prehistory of Afro-Eurasia and the rise of Arabian city-states. It then offers a biographical treatment of Muhammad, followed by an assessment of the spread of Islam, and its splintering into diverse factions that occurred in the centuries following Muhammad's death. Resources, including a timeline, help readers contextualize and connect the various regional developments during Islam's early period.