Modern editors of Othello unanimously and silently adopt the Folio (1623) text as their copy text but emend it in light of the quarto (1622) text at III, iii, 97. Neither of the two reasons for emendation, textual corruption or literary unintelligibility, applies. A critique of textual editing shows that, given knowledge of the many and various possibilities in the transmission of a text from authorial page to commercial print, emendation is problematic and probabilistic. The Folio is not textually corrupt at this point. A critique of literary criticism shows that diverse approaches to interpreting Othello’s jealousy, all assuming the quarto reading, fail to explain its sudden and unexpected onset. The only effort to address the crux fails to show the Folio unintelligible because of flaws in its interpretation of the Folio text. Yet the Folio text was intelligible to Shakespeare, his company, and his audiences. For it depends on literary knowledge which modern editor lack or overlook. It exploits the features of courtly love in English chivalric romance, especially the role of the intermediary, with his propensity to betray his purported function. The dual conclusion: if editors use the Folio has their copy text, they should retain and explain the Folio reading; and they should consider that textual editing may require more literary history as an aide than they realized.