Leaves of Grass - Wikipedia

On July 4, 1855, in Brooklyn, New York, the first edition of Walt Whitman's book of poems, "Leaves of Grass" was published. It was and is still influential throughout the world.
From the article:

"The poems of Leaves of Grass are loosely connected, with each representing Whitman's celebration of his philosophy of life and humanity. This book is notable for its discussion of delight in sensual pleasures during a time when such candid displays were considered immoral. Where much previous poetry, especially English, relied on symbolism, allegory, and meditation on the religious and spiritual, Leaves of Grass (particularly the first edition) exalted the body and the material world. Influenced by Ralph Waldo Emerson and the Transcendentalist movement, itself an offshoot of Romanticism, Whitman's poetry praises nature and the individual human's role in it. However, much like Emerson, Whitman does not diminish the role of the mind or the spirit; rather, he elevates the human form and the human mind, deeming both worthy of poetic praise.

With one exception, the poems do not rhyme or follow standard rules for meter and line length. Among the poems in the collection are "Song of Myself", "I Sing the Body Electric", and "Out of the Cradle Endlessly Rocking". Later editions included Whitman's elegy to the assassinated President Abraham Lincoln, "When Lilacs Last in the Dooryard Bloom'd"."