Did Muhammad use the sword to spread Islam across the Arabian Peninsula? In the Koran, Allah commands that there are to be no forced conversions to Islam. But the Koran also states that Muhammad spoke for Allah and must be obeyed. And over the centuries authoritative Muslim scholars have repeatedly written about a large number of incidents in which Muhammad offered non-Muslims, including entire Arab tribes, the stark choice of converting to Islam or being killed. Did Muhammad really make permissible what he knew Allah had made impermissible? In his fourth book about Islam Dr. Kirby investigates this question. He relies extensively on the translated writings of early authoritative Muslim scholars to take a historical approach to the examination of Muhammad and the early years of Islam. His conclusions may be surprising and troubling, but they are essential to understanding Islam. Dr. Kirby is the author of Letting Islam Be Islam: Separating Truth From Myth, a book that was reviewed in an Arabic language online publication of the Beirut Islamic University, Beirut, Lebanon. The reviewer noted that Letting Islam Be Islam "...provides a very deep understanding of the Koran and the Sunnah" and "is an excellent resource to guide you in understanding the enormous plethora of information about Islam" (Islamic Literature, Issue No. 73, 2013). This review was translated from the Arabic by Dr. Mark Christian, a native Arabic speaker.