This article aims in analyzing genealogically the understanding of intelligence and how this reflects and gives meaning to conflicts that took place on the second half of the twentieth century and the first half of the twenty first century -more specifically the Second World War, the Cold War and the Iraq War.We seek to trace this analysis of intelligence through the development, during the aforementioned historical periods, of the interdependence between its strategic and investigative aspects.We work with the Iraq War as an example of a conflict in which both aspects were very clearly mixed up.In this sense, we use the Battle of Nasiriyah as a case study to show how the use of the intelligence was vital for the American army to have information about the Iraqi army, what consequently allowed them to set up the tactic moves in the battlefield.What happened in Nasiriyah was, then, vital for the American army to advance in Iraqi territory.