From the introduction by Galway Kinnell:

The poems of Walt Whitman meant little to me when I read them in high school and college. Luckily, when I was teaching at the University of Grenoble in my late twenties, I was required to give a course on Whitman. My experience of Leaves of Grass then was intense. . . . Soon I understood that poetry could be transcendent, hymn-like, a cosmic song, and yet remain idolatrously attached to the creatures and things of our world. . . . Once again, as when I first began writing, it seemed it might be possible to say everything in poetry.