In this short book, the renowned French thinker Olivier Roy presents a provocative new perspective on jihadism in Europe, one that has become known as the ‘Islamization of radicalism’ hypothesis. Rather than a political or ideological import from the Middle East, European jihadism is but the latest in a long series of youth revolts. The underlying cause is cultural dislocation, which in turn stems from immigration, globalization, and secularization in late 20th century Europe. Relying on a sample of 140 mostly French and Belgian jihadis, Roy downplays the role of Islam and Islamism, noting that most jihadis have no religious education and radicalize outside mosques. He also tones down objective grievances, saying the militants are usually not from the conflict zones they are angry about, nor from underprivileged suburbs. Instead they form a subculture outside traditional institutions, made up primarily of second-generation immigrants, who face a peculiar cultural dislocation that the first and the third generations do not. Ideologically unsophisticated, they are guided by superficial intuitions about suffering Muslims abroad and the ideal of the avenging hero. As such, he argues, they have much in common with other youth rebels, especially the far left in the 1970s. What is new is the modern jihadi fascination with death, which borders on nihilism. The argument is stimulating, but empirically unconvincing. It ignores much recent research and the over thirty biographical datasets with different patterns. It dismisses as insincere the entire jihadi discourse about geopolitics, the caliphate, and afterlife rewards. It also skirts the issue of why so many people outside Europe also become jihadis. Roy is on to something important, but does not tell the whole story.