I think what stuns me the most about Walt Whitman’s poetry is how old it is chronologically, and how new (or young?) stylistically.  He wrote much of his audaciously hubristic, rhythmically unrhymed, New Agey but never fuzzy poetry before they had electric lights, before he saw the Civil War tear up America.  England was just warming up to the Victorian period, man.  This’ll blow your mind: the first edition of Whitman’s Leaves of Grass was published in 1855; that’s just five years after William Wordsworth died.  Wordsworth was the guy who called for poets to write in the language of the common man, and tried to follow his own advice.  Before Wordsworth, poets were pretty much still writing like John Milton.  Too bad Wordsworth couldn’t have lived a little longer to see Whitman do this:

The spotted hawk swoops by and accuses me,

he complains of my gab and my loitering.

I too am not a bit tamed, I too am untranslatable,

I sound my barabaric yawp over the roofs of the world.

The last scud of day holds back for me,

It flings my likeness after the rest and true as any on the shadow’d wilds,

It coaxes me to the vapor and the dusk.

I depart as air, I shake my white locks at the runaway sun,

I effuse my flesh in eddies, and drift in in lacy jags.

I bequeath myself to the dirt to grow from the grass I love,

If you want me again look for me under your boot-soles.

You will hardly know who I am or what I mean,

But I shall be good health to you nevertheless,

And filter and fibre your blood.

Failing to fetch me at first keep encouraged,

Missing me one place search another,

I stop somewhere waiting for you.

(from “Song of Myself,” 1855)