Scant critical attention has hitherto been paid to T.S. Eliot’s “The Love Song of J.Alfred Prufrock” in relation to the excised “Prufrock’s Pervigilium” section preserved in his “March Hare” Notebook and why Eliot might have deleted it. Reading the “Pervigilium” back into “Prufrock,” this article argues that “Prufrock” sings of its own making and that of its poet’s consciousness in the “Pervigilium” section. In this way, the poem anticipates Eliot’s depersonalization (or catalysis) theory of poetic creation in “Tradition and the Individual Talent,” where the deletion of the “Pervigilium” is prescribed. F.H. Bradley’s Appearance and Reality and Walter Pater’s Marius the Epicurean, meanwhile, emerge as important influences on Eliot’s depersonalization theory and the dissociated poetic consciousness of “Prufrock.” As a result of the latter influence, this article also contributes to the ongoing examination of Eliot’s indebtedness to the writers in Decadent England.