Terrorist attacks, ISIS, religious conflicts and humanitarian crises are recurrent issues widely covered by the media. And, for many people, Islam is the religion involved one way or another in all of them. But what do we actually know about Islam? What are the multiple trends of Islam today? How can we identify religious extremism? How can we explain the complex relations maintained between Western society and Islam in Europe? Where does this rejection, so strong in Western society, of Islam and vice versa come from? These are the questions that Jocelyne Cesari deals with in depth in this article published by the European Institute of the Mediterranean. She also highlights the need for education about the Muslim religion in different European contexts to avoid radicalizations among the populations that could cause social fractures.