Dealing with radical Islamist ideologies successfully is one of the big challenges of our time. This book is analyzing major causes of the ideology of al-Qaeda and of Iran, both often described as evil. It offers solutions to mitigate the violence of radical Islamist ideologies and eventually to dissolve them. It shows that the ideology of al-Qaeda is very much rooted in the Israeli-Palestinian conflict. With respect to Iran, it highlights the fact that the event of the overthrow of the democratically elected prime minister of Iran, Mohammad Mossadegh, and the destruction of the young Iranian democracy by the CIA in 1953 is the most important reason for the severe mistrust and the hostilities of Iran towards the United States. This book concludes, among others, that a comprehensive peace between Israel and the Palestinians is a requirement to significantly mitigate the violence of radical Islamist ideologies. This needs to go hand in hand with strengthening the condemnation of the distorted religious ideology of al-Qaeda and ISIL by religious authorities of Islam.