The main subject of this book concerns the Muslim immigrants in Europe. It includes the entire history of Islam vis-a-vis Europe since the 7th century, prescribing useful dos and donts for current European policymakers. Europeans have developed negative predispositions toward Muslims, sometimes even distinctly perceiving them as foes. The British greatly value the recollection of their glorious erstwhile empire, thus, when it broke-up, they enabled former subjects of the Crown to settle in the UK, as if to build a miniature duplicate of their empire within Britains borders. Hence, the British did not perceive former colonies Muslim immigrants as foes, unlike continental Europeans, but as British subjects. Generally, Europeans intend to fill the individual Muslim immigrants needs as a citizen, according to the liberal approach. The expectation, however, is that Muslims, as a group, would become culturally integrated within the absorbing society. That approach bewilders the European Muslims. Many Muslim immigrants experience discrimination in Europe. The continental European approach toward Muslims, stemming from prejudice and fear, made some immigrants aggressive. The main divergence between European society and Muslim immigrants is due, foremost, to certain collective memories of the native Europeans. That insight is elucidated by comparing European and American societies. The American, found in a country built by immigrants tends to adapt to a variety of new immigrants, Muslims included. Conversely, European society is fundamentally incapable of truly incorporating immigrant culture and practices, which it perceives as a threat, especially concerning Islam. It is, therefore, the Europeans who hold the key to alter the destructive dynamics, not the Muslims. Muslims and Arabs within their countries suffer the frustration of remembering their Golden Age when the Europeans were deeply mired in the Middle Ages. Nowadays, the Arabs and Muslims have not been able to lift themselves back to their former state. That frustration may be compared to the German frustration in the 1920s being split up into distinct German states the consequence of which was the mass destruction of the European Jewish population. The splitting of the Germans, while suffering from lack of one uniting national myth, had brought on the adoption of a German race theory which Adolf Hitler offered to the Germans and had led to the Holocaust. Frustration may turn people rather aggressive, and Iran or some Arabs (like the members of ISIS) aided by Muslims in Europe might end up using weapons of mass destruction against Europe. The case of ISIS is therefore elaborated upon, in detail, in this book. The successful integration of the Muslims in Europe may help somewhat; indeed, this book aims to promote such an accomplishment. The French approach is uniquely rather rigid towards Muslim immigrants, as a group and individually. Hence, there is no mental confusion among Muslims there and a significant portion of the Muslims in France see themselves as French better integrated than other Muslims in Europe. The best policy the Continental Europeans may adopt is the French approach.