The reciprocal relationship of text and act (to borrow an established formulation) is acutely demonstrated in the compositional history of Beethoven’s late string quartets. As is well known, Beethoven was able to draw on the resources of his ‘Leibquartett’ – Ignaz Schuppanzigh, Karl Holz, Franz Weiss and Joseph Linke – in shaping and refining many details of the scores. The conversation books for 1825–26 preserve precious record of exchanges, above all with Holz and Schuppanzigh, concerning notation and execution as well as the first performances of the three ‘Galitsin’ Quartets, op. 127, 132 and 130. More recently, Nancy November, drawing a parallel between Beethoven’s interactions with his personal performing ensemble and her own work with the Fitzwilliam String Quartet, has argued that performance can inform not just composition but editing also. And contemporary performance scholarship benefits more generally not just from the increasing availability of recordings but from the testimony of performers themselves. Accessing the performing mores of earlier generations is, of course, another matter. Writing of performances of the late quartets prior to the mid-nineteenth century, Christina Bashford makes the obvious point that ‘the nature and quality of the actual performances ¬– lost to thin air, unlike ones of the gramophone era – can of course never be recovered’. Reviews and personal accounts, inasmuch as these survive, assist in the imaginative reconstruction of events; and projects such as CHASE and TCHIP have sought to harness the potential of performing editions, some supplemented with performance markings, in advancing the study of performance practice, as well as bringing to bear the importance of ‘pre-performance’ issues.