 And, of course, the historian faces an even more basic intellectual task: that of discovering and making sense of the archival and historical information that exists about a given event or time in the past. Historical data do not speak for themselves; archives are incomplete, ambiguous, contradictory, and confusing. The historian needs to interpret individual pieces of evidence, and he or she needs to be able to somehow fit the mass of evidence into a coherent and truthful story. Complex events like the Spanish Civil War present the historian with an ocean of historical traces in repositories and archives all over the world; these collections sometimes reflect specific efforts at concealment by the powerful (for example, Franco’s efforts to conceal all evidence of mass killings of Republicans after the end of fighting); and the historian’s task is to find ways of using this body of evidence to discern some of the truth about the past.