Revered by some artists and scholars as the origin of 'experiential truth' and contested by others in their zealous custodianship of the factual record, testimony occupies an awkward place in historiography. The debate over the authority of the witness is decidedly pronounced in the field of Holocaust studies, in which considerable emphasis is placed on the value of witness accounts as a conduit of historical knowledge. This chapter interrogates the utility of the concept of 'truth' in the appraisal of literary Holocaust testimonies. Drawing on Peter Lamarque's concepts of 'thought-theory' and 'narrative opacity', the chapter offers an alternative reading of the value of testimony that is not based on dubious truth-claims but recognises nevertheless the unique contribution of testimony to discourse on the Holocaust.