Auden was a great poet and a provocative professor, but he was not always the ideal library patron. His sometimes indecipherable scrawl probably provided an interesting challenge for those who attempted to parse his library call slips.
A small selection of Auden's call slips: Freud, Dostoevsky, Joyce, Melville, Augustine, and Kierkegaard.
*From The Dyer's Hand and Other Essays (NY: Random House, 1962): "As readers, most of us, to some degree, are like those urchins who pencil mustaches on the faces of girls in advertisements." (p. 4)