Elizabeth Polack (fl. 1834–1843) is the earliest known Jewish woman playwright in Britain. In this essay, I detail the historiographical difficulties in researching Polack's lost play The Echo of Westminster Bridge (1835), which lived vibrantly in cultural memory for a century even though the play itself disappeared and its author receded into obscurity. One problem with becoming modern is confronting the increasing inaccessibility of the past. I demonstrate that, notwithstanding some confusion about authorship, Echo is by Polack and that her melodrama made a long-standing impact. I delineate the special problems associated with using a twenty-page Skelt's toy theatre condensation of the full-length stage play to reconstruct some of its main features. Then I speculate that – like Polack's best-known play, Esther, The Royal Jewess (1835) – Polack's The Echo of Westminster Bridge also potentially nudges forward the cause of Jewish emancipation. But how can one study a play that was popular and influential but has ceased to exist? That metacritical problem – the ephemerality of theatre and its compounding challenges for research – is part of the condition of the modern.