Leaves of Grass is a collection of poems written by Walt Whitman. Leaves of Grass was published in 1855.
The common themes among the verses in Leaves of Grass is man's transcendence of his physical limitations and the desire to form a spiritual connection with nature and, ultimately, the universe. The title itself alludes to the theme of nature and the poet's observations of his surroundings.
Some of the poems are written in the first person. However, others are written in the second person, hence the usage of "you" to address the reader. "You" also addresses Walt Whitman himself, as the narrator can be understood as nature or a form of divinity found in nature. This literary technique is most prominent in the poem "Song of Myself."
In "Song of Myself," Whitman speaks to both an individual person (himself) and humanity as a whole.
For instance, in this excerpt from "Song of Myself," Whitman uses the second person to frame a conversation:
You are also asking me questions and I hear you, I answer that I cannot answer, you must find out for yourself.
This literary technique is effective in Leaves of Grass because the poems are written like a journal—in which Whitman expressed his thoughts and philosophies in the form of a dialogue.
When Whitman uses "you" twice, he is reiterating a statement about his position within the universe.