This article is an overview of the evolution of Islamic radicalism during the 19 th - 21 st centuries. It demonstrates that nineteenth century Islamic radicalism is based on the ideas of pan-Islamism, whose main representatives are J. al-Din al-Afghani and M. Abduh. In turn, Islamic radicalism of the twentieth to twentyfirst centuries is based on the ideas of Islamic fundamentalism. Its main representatives are H. Al-Banna, S. Qutb, the Deoband movement, al-Maududi and R. Khomeyni. Pan-Islamic theories of the 19 (...) th -20t h centuries are based on the thesis that people who seek liberation from colonial oppression should merge. However, scholars have different views on the union of the Muslim world. It was, once, regarded as a combination of historical circumstances and the political realities of the nineteenth century. These were further shaped by the basic idea of Islamic fundamentalism in the twentieth to twentyfirst centuries, which is Salafiyya, or a return to “pure Islam”, a revival of active faith traditions and the union of all walks of life under the Sharia law and strict interpretation and application of its rules. The instruments used by Islamic fundamentalists and radicals to implement it have been the Islam-related slogans for Takfir and Jihad. But in the 21st century, integration and globalization have started playing a significant role. Various geopolitical forces are using various tools, including the idea of Islamic radicalism. (shrink)