"O Me! O Life!" is part of Walt Whitman's collection of poems Leaves of Grass. In "O Me! O life!" Whitman raises an existential question: "What good" can be found in life amid "the endless trains of the faithless" and the "cities fill'd with the foolish"?
The primary poetic technique that Whitman uses in this poem is anaphora: the repetition of the same word or phrase at the beginning of successive clauses or verses. The bulk of the poem consists of phrases that begin with the word "of":
Of the endless trains of the faithless, of cities fill'd with the foolish,
Of myself forever reproaching myself, (for who more foolish than I,
and who more faithless?)
Of eyes that vainly crave the light, of the objects mean, of the
struggle ever renew'd,
Of the poor results of all, of the plodding and sordid crowds I see
Of the empty and useless years of the rest, with the rest me intertwined
Another technique Whitman uses is alliteration--the repetition of initial consonant sounds. In lines 2-4, for example, Whitman uses 7 words that start with the letter f: faithless, fill'd, foolish, forever, for, foolish, faithless. From line 7 to the end of the poem, 4 words start with the letter p: poor, plodding, powerful, play. It is interesting to note that powerful and play are nearly the opposites of poor and plodding.