We know that as he wandered the streets, as he rode in the omnibuses, probably as he sat in lectures and in the opera, he scribbled in small notebooks and on scraps of paper he stuffed in his pockets. We know he then transcribed them, ordered them, wrote them down, then set the type for the first editions of his great work himself. . . . And there it was, on the page. . . . We know, we know, we know. . . .

"He was learning his craft," we like to think. Always with the notion of craft comes the implication of progress, improvement. The very word craft seems to have inherent in it the precept that more you practice your art, the more you labor at it and study it, the more craft you'll have, the better you'll be able to effect your poetry, or anything else. This can be quite a debilitating credo—I've known poets who for all intents and purposes spent their life learning their art, preparing to write poems, but never getting around to actually doing it. Similarly, critics will sometimes make up a lengthy biography for poets whose precociousness seems to be a denial of the normal evolution of the attainment of knowledge. It can seem completely unfeasible to believe that Keats or Rimbaud didn't somehow do something practical to absorb all they had to in the preparation of their poetic activities. I once read an article about Rimbaud that set out to prove that his very unlikely knowledge of so many matters of the history of poetics, and of history itself, had to have been the result of the thousands of hours he'd spent in the Bibliothèque Nationale, sneaking off presumably from the rather bohemian time-wasting that comprised most of the actual life of the seventeen-year-old he was when he wrote his greatest poems.

Whitman's craft, his skill, was supreme during that first blazing burst when he was compiling the 1855 edition of Leaves of Grass and adding to it in the nearly as inspired years afterward. But though he had been for some years a productive journalist, there's still no way really to account for how he accumulated in such a short time so many singular methods, so many facets for the expression of his talent; there was no place he could have "learned" his craft: it evolved along with his identity, with his very self.

The new way of composing must have come all at once; I imagine it must have felt like some kind of conversion experience. There are very few signs before the 1855 edition that this great thing was about to occur. It's as thought his actual physical brain went through some incredible mutation, as though—a little science fiction, why not?—aliens had transported him up to their spaceship and put him down again with a new mind, a new poetry apparatus. It is really that crazy.

And, most important, we don't know where his music came from; though there are isolated lines in the notebooks that offer clues, we'll never really know when he first fully intuited, and heard, and knew, that surge of language sound, verse sound, that pulse, that swell, that sweep, which was to become his medium, his chariot—just to try to imagine him consciously devising it is almost as astounding as it must have been for him to discover it.

It's essential to keep in mind that in poetry the music comes first, before everything else, everything else: until the poem has found its music, it's merely verbal matter, information. Thought, meaning, vision, the very words, come after the music has been established, and in the most mysterious way they're already contained in it. Without the music, there's nothing: thought, merely, ideation; in Coleridge's terms, not imagination, just fancy; intention, hope, longing, but not poetry: Wait, Muse! Let me sing it to you, wait! That might be what drives poets to desperation, or worse: the waiting, the wanting, the sensing of the cadences, the melodies, but being unable to force them. It's also probably what tends poets towards manic-depressiveness, because when the music does finally arrive, the mix of relief and exaltation is unreal, beyond self, ego, consciousness and conscience.

Usually the music seems to come along simultaneously with the words and the matter, but not always. Mandelstam spoke of hearing the music for a poem, feeling it, before it had any words at all. Pavese said: "By means of murmuring, I gave a rhythm to my poems." Neuroscientists say now that there are separate areas in the brain, individual "modules," for one and the other. Poetry's splendor, its seduction, its addictive potential surely resides in this bringing of separate psychic realms together in one mental and emotional speech-act, thought-act. Dante has the poets in Limbo going off together alone to speak of things that are not to be revealed to others, even in his Comedy of revelation. What could these things be other than that most profound and most blatant secret of the poets: that only they can generate this unlikely marvel, language music—in great poets a music immediately recognizable and resolutely unique?

In "Song of Myself," Whitman chants aloud the secret to himself:

My voice goes after what my eyes cannot reach,
With the twirl of my tongue I encompass worlds
    and volumes of worlds.
Speech is the twin of my vision . . . . it is
    unequal to measure it self.

From C. K. Williams on Whitman, copyright © 2010 by C. K. Williams. From the Writers on Writers Series, Princeton University Press.