The author is specialist in Islamic studies. He graduated from the University of Strasbourg III. He practiced for nearly twenty years as an academic teacher in public law and international relations. Clash of civilizations or understanding, complementarily and mutual respect between civilizations? Judging without knowing or understanding before judging? An objective and well-documented approach to assist in understanding Islam, in general, and the relation of Islam to violence in particular, contained in a reference book about a subject of world importance.