First published in 1855, this poetry collection by American poet, Walt Whitman is a celebration of his philosophy of life and humanity, and spans the human element from the perspective of both the mind and the body. Instead of focusing on religion or spirituality, Leaves of Grass focuses mainly on celebrating the body, exalting nature, praising the senses, and the material world. He was greatly influenced by Ralph Waldo Emerson and the Transcendentalist movement. The writing, which was highly controversial and condemned as immoral due to its explicit sexual imagery, is with the exception of one poem, an innovative free style verse which does not rhyme or follow the standard rules for meter and line length.

This collection of loosely-connected poems was a work in progress through over four decades. When Whitman published the first edition of Leaves of Grass at his own expense, it was a volume of only twelve poems. He spent most of his life writing and rewriting the book until at the end, after four decades, he published the final version containing over 400 poems only weeks before he died in 1892.

In what is regarded by many scholars, to be a completely "do-it-yourself" project, the collection has infiltrated popular culture and is recognized today as one of the central works of American poetry. Many movements have used Whitman's work throughout the years as a means to further social and political change.