Early Editions of Leaves of Grass
•1855 Self-published the first edition
•1856 Added new poems and revised old ones.
•1860 Began grouping poems thematically; includes “A Child’s Reminiscence,” which will become “Out of the Cradle, Endlessly Rocking” •1867 Incorporates Drum-Taps (1865), including “When Lilacs Last in the Dooryard Bloom’d” and “O Captain, My Captain”
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This is but a rough sketch of the versions of Leaves of Grass.  Whitman was to publish many versions and variations, of which this list gives only the principal ones.

In addition, William Michael Rosetti published a selected edition of the poems (American poems) in 1872, and his efforts on Whitman's behalf led to many subscriptions for the 1876 Centennial edition of the poems.