Synopsis Jihad an Islamic term is a religious duty of Muslims. In Arabic, the word Jihad is a noun meaning "struggle". Jihad appears frequently in the Quran and common usage as the idiomatic expression "striving in the way of Allah". A person engaged in Jihad is called a Mujahid, the plural of Mujahideen.

A minority among the Sunni scholars sometimes refer to this duty as the sixth pillar of Islam, though it occupies no such official status. In Twelver Shi'a Islam, however, Jihad is one of the 10 practices of the religion. This book focuses on why and how such a seemingly radical development took place. Basing his hypothesis on evidence from the Qur'an and early Islamic literary sources, Firestone locates the origin of Islamic holy war and traces its evolution as a response to the changes affecting the new community of Muslims in its transition from ancient Arabian culture to the religious civilization of Islam.