An overview of large-scale violence by Islamist extremists in key African countries, is presented in this paper. The paper seeks an overview of the evolution of the associated terrorism through quantitative and contextual analysis using various large data sets. The focus is on the development and links among countries experiencing the worst of this phenomenon, especially Algeria, Egypt, Tunisia, Libya, Mali, Nigeria and Somalia, as well as the impact of events in the Middle East on these African countries. This paper argues that one should distinguish between events in North Africa, where developments are closely related to and influenced by what happens in the Middle East, and the evolution in north-east Nigeria of Boko Haram, which has a character more closely resembling a sect. Somalia, the final country to be included here, finds itself somewhere between the situation in North African countries and that of Nigeria, in that al-Shabaab is more closely linked to events outside its immediate environment but does not form part of the trajectory of North African countries although the divided clan politics in Somalia resemble the factionalism currently evident in Libya.