The article examines Simon Wiesenthal’s life-long preoccupation with the Holocaust, by using Paul Ricoeur’s discussion of the two modes of dealing with the past – those of ‘memory’ and ‘history’ respectively – as a point of departure. Nevertheless, the article aims to approach the varying forms and expressions of this preoccupation in an integrated fashion, analyzing it as different means of achieving one and the same purpose: giving a public ‘collective testimony’ of the Holocaust. Departing from Wiesenthal’s own experiences, as well as testimonies of how the events of the Holocaust affected his own larger family, and testimonies of events taking place in his original Heimat – the area of Eastern Galicia that he stemmed from – Wiesenthal’s work in collecting testimonies of Nazi crimes gradually aggregated into a special form of ‘collective testimony’ of the Holocaust.