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Thematic changes

Whitman edited, revised, and republished Leaves of Grass many times before his death, and over the yearshis focus and ideas were not static. One critic has identified three major "thematic drifts" in Leaves of Grass: the period from 1855 to 1859, from 1859 to 1865, and from 1866 to his death.

In the first period, 1855 to 1859, his major work is "Song of Myself", which exemplifies his prevailing love for freedom. "Freedom in nature, nature which is perfect in time and place and freedom in expression, leading to the expression of love in its sensuous form." The second period, from 1859 to 1865, paints the picture of a more melancholic, sober poet. In poems like " Out of the Cradle Endlessly Rocking " and " When Lilacs Last in the Dooryard Bloom'd ", the prevailing themes are of love and of death.

From 1866 to his death, the ideas Whitman presented in his second period had experienced an evolution: his focus on death had grown to a focus on immortality, the major theme of this period. Whitman became more conservative in his old age, and had come to believe that the importance of law exceeded the importance of freedom. His materialistic view of the world became far more spiritual, believing that life had no meaning outside of the context of God's plan.