What qualifies an expert? In the area of Eastern European history, how does this expert's own experience of his (more rarely her) area of expertise affect that qualification? Taking into account the historical context, what is the connection in his or her life between Eastern Europe and violence: was it a place where he or she suffered from violence, or did he or she exert violence there? Is the experience of violence reflected in his or her expertise? If so, how — and, more importantly, when? Taking the individual backgrounds of experts in Poland and Germany who lived through World War II, I set out to compare the impact the war had on their lives and the disruption and continuity in their acquisition and praxis of expertise. For this research, I focused on 3 institutions providing expertise on foreign relations in Poland, West and East Germany, from which I selected the experts working on issues related to Eastern Europe, in the fields of security, history and law. Facing a very diverse and rich corpus, I developed an analytical tool in the form of a visualisation that would provide me with an overview of the biographical data and the intellectual production of the experts I was observing. The result is a conceptual model that shows side by side the evolution of the expertise and the experience of the expert. Since the visualisation lies in the schematisation of data that are partially given (e.g. date of birth), and others that are partially built (experience of violence), one can ask how the visualisation of biographical trajectories and intellectual production can be used as a heuristic and communication tool for the researcher; or what is the use of drawing non-computed data? According to Jacques Bertin (Bertin 1981), a graphic theorist, the visualisation of data should make a multiplicity of data readable to humans. The data should be organised in such a way as to present relationships between elements of data and provide the reader with answers on those relationships. The visualisation is fully integrated in the iteration process of the research. In an effort to synthesise my corpus, I build two pillars: one for the biographical trajectory and one for intellectual development. The first used the biographical data: date of birth and death, career stages, etc. The second looked at intellectual production: books, articles, etc. Here we have examples of biographical trajectories, showing the carrier steps of three German experts, with their academic experience in green, their journalistic one in purple and their military one in red. The experience of violence is represented with wavy lines; parallel when the violence is endured, reversed when exerted. The dotted lines represent professional instability. Here at one glance, one can see the impact the war had on their careers, in terms of mobility and violence experience or practice.