The religion of almost one quarter of the globe, from Africans to Asians to Indonesians to Europeans, Islam today is either celebrated as a universalist religion of peace or condemned as fanatical, militant and intolerant. Jews lived for centuries relatively peacefully and successfully under Islam, and today there are almost no Jews living in Muslim-majority countries – both are factually true. The reality, both historically and in our own days, can be both, and a deep knowledge of the history, culture and development of Islam are crucial to evaluating both past and present.