Hugh Kenner's The Pound Era, which reshaped the discussion of Pound in the 1970s, and in some ways re-ignited the debates about Pound's politics (because, for Kenner, Pound's fascism by no means mooted his poetic centrality), was published in 1973. Not knowing much about Kenner's earlier work, I'd always assumed it was written in the late 60s and early 70s; such a big book surely took a while to make.
Yesterday I spent the day reading around in the Poetry magazine papers at the University of Chicago and read Kenner's correspondence with Poetry editor Henry Rago in the years 1957, '58, '59, '60. And in a letter to Rago dated 1960, Kenner told Rago, "I plan a Great Book" which will use Pound's "career as a central image," etc. etc. There you go. Kenner first conceived of The Pound Era in 1960.
In one sense, the Pound era is 1960-71. Kenner was incensed by Richard Ellman's biography of Joyce, which was also published in 1960. His book on Pound is in part a corrective.