Abstract: Generating data is analytically crucial for the identification of empirical trends and for theoretically explaining the occurrence, escalation and duration of war. Practically, it contributes to the objective of developing preventive measures. In order to evaluate the evolution and transformation of war, in this article, we first examine the macro-trends for the period between 1946 and 2007 compiled in a new Consolidated List of Wars. In the second part, we compare data from major data-gathering projects to assess both their degree of convergence and their usefulness for the scientific study of war. In the final section we open the black box of war. We present disaggregated violent events for the case of Somalia which is a striking example of organized violence between mostly non-state armed groups, the collapse of state authority and variations of violent events in time and space.