Johann Caspar Lavater’s Vermischte unphysiognomische Regeln zur Selbst- und Menschenkenntnis (1787) is a classic work of Enlightenment thinking that entered English circulation with a split identity. Published as Aphorisms on Man in 1788, it was brought before an English audience through the printmaking skills of William Blake and the agency of Lavater’s childhood friend Henry Fuseli. However, Lavater might well have recalled the saying “Traduttore, traditore” (Translator, traitor). Fuseli had not failed to close the lexical gaps between the German and the English. Rather, his ideas had transformed the work, from its ambiguous frontispiece through to its concluding lines—interventions that challenged Lavater’s claim to authorship of the book. If the usual stories told about Aphorisms on Man describe the volume as a “product of friendship” or a “labour of love,” I turn this convivial alliance on its head to suggest that a closer look at its behind-the-scenes production reveals a different narrative, one that pivots on rivalry as much as collaboration.