This book tells the story of uneasy relations the Western Christendom had or having with the Eastern Islamic and Jewish world. It covers a huge sweep of both time and place, begins in the seventh century and extends into the twenty-first. Its boundaries are Morocco and Algeria to the south, and Vienna to the north, the Atlantic to the west, and the Arabian Sea and the Indian Ocean to the east. We can read them and see how they made an impact on the human imagination. The deep cause of their hostility seemed hidden beneath the religious or cultural explanations, underlying political and economic rivalries, hatred and animosities, personal ambitions and vanities, chance and accident. Inter-faith understanding for peaceful coexistence is a minimal need of our time. It is not the same thing as love or friendship. To the contrary, it is an expression of distance, an acknowledgment of boundaries that will remain. It is informed by an attitude of "live and let live". Coexistence is an ideal without illusions. In a pluralistic society, ethnic and cultural differences are not abolished. They are legitimized, and society strives to guarantee that the law will be blind to them. We are increasingly confronted by people and groups whose worldviews are utterly different from ours, and these people are our neighbors, co-workers, and schoolmates of our children, our in-laws, our clients, our employers and more. In today's world of global connectedness, we must develop the capacity to dialogue and create relatedness with people vastly different from us. We do not need to be the same, but we should find just enough similarity between us that we can hold hands as fellow travelers in this life, all the while mindful of our differences in myriad ways.