In his book "Islam and Islamism: The Dilemma of the Muslim World", P. R. Demant shows a depiction of the evolution of the phenomenon of Islamism (or "political Islam"). Although this graph cannot include every single detail in the history of Islamism, I believe it is one of the best visualizations that help understand this complex subject. I have enhanced the original black and white graph by adding color and portraits of important personalities. In this form, it should be even easier to understand. Click on the picture to enlarge.