In a documentary play in which actors represent living or historical people, textual artefact is replaced by creatively embodied document. Every stage of the construction of that document, from a subject's recall of events, to a researcher's transcription of the subject's testimony, to performance, is an act of improvisation. Reflecting on Nanay: a testimonial play, this paper examines the document as a necessarily creative construction. It describes improvisative decisions made at every stage of the rehearsal process, how they resulted in naturalistic or non-naturalistic staging, and how spectators and researchers correlated truth claims to the various theatrical genres employed. Referencing cognitive and event theories, Ferguson argues that the spectator engages with embodied performance somatically, and that “identification” based on mutual embodied encounter becomes critical to the spectator's acceptance or rejection of a documentary play's truth claims. [ABSTRACT FROM AUTHOR]