One of the most fascinating, and frustrating, footnotes I’ve ever come across—to my mind, one of the most beguiling footnotes in English literature—is found in A. E. Housman’s “The Name and Nature of Poetry,” a lecture he delivered at Cambridge in 1933. As its title suggests, the lecture was speculative and broad-ranging, and hence was a departure for Housman, who repeatedly called himself “no literary critic” and who usually restricted his lectures to tightly focused examinations of classical texts, about which he spoke, according to one of his students, in a “level, impassive voice . . . without enthusiasm but with an athletic spareness.” By temperament a surpassingly wary and punctilious man, Housman had profound reservations about presenting to the public anything that might resemble breezy, insupportable generalizations, and the composing of his lecture caused him, as his biographies attest, no end of inner trouble and turmoil.

Before unfolding his central thesis (the notion that poetry “is not the thing said but a way of saying it,” that it “is more physical than intellectual”), Housman informed his audience that his immediate impulse had been to select another topic entirely, that of The Artifice of Versification. This is a subject, he assured his listeners, that belongs to the methodical mind—to “the man of science,” in fact, who would be “fitter for the task than most men of letters.” He went on: “This latent base, comprising natural laws by which all versification is conditioned, and the secret springs of the