The book provides a history of the tumultuous evolution of the populations living in the Lake Chad basin since the 9th century and their resilience in the face of anthropological and environmental changes. The difficulties and the adaptation of the populations in the face of extremism, the weakness of the presence of the States and their national armies were evoked. The causes of adhesion to the extremists are revealed as well as the various types of conflicts and their imbrications which prevail within the various communities living in the Lake Chad basin. The author discusses the triggers that lead to the recruitment of extremist groups by the population, while also mentioning the different ways in which non-state armed groups are created and expand, and the different forms of violence they inflict on both the civilian population and the armies of the Lake Chad Basin States. In the face of asymmetric attacks, some national armies have developed moral resilience and have become more resilient as non-state armed groups have evolved and changed their modus operandi. The book asks the real essential questions about the existence of populations.