Comparative analysis of performance texts, however, can be challenging, especially in regard to physical comparison of otherwise unrelated print and manuscript witnesses. This chapter presents a parallel-text approach to the analysis of performance-based playhouse materials, manually transcribed, and digitally presented and preserved in a near-ubiquitous spreadsheet platform. It explores this technique through a prototype digital edition of multiple performance texts, which brings together two early print witnesses of Shakespeare's Richard III and ten selected promptbooks and performance editions. The chapter aims to rehabilitate performance texts as means of historiographical evidence. Digital visualization is particularly useful in the context of wide variation among performance texts. Promptbooks, playhouse texts, and performance editions, as "versions of the play", are almost always unique to the productions they serve, entirely "imbedded in a specific time", rather than pointing to a sequential provenance of source and influence or hypotheses of "ur-text".