1897. Volume Three of Three. Whitman is considered by many to be the greatest of all American poets. In his work, he celebrates the freedom and dignity of the individual and sings the praises of democracy and the brotherhood of man. Leaves of Grass is unconventional in both content and technique and is probably the most influential volume of poems in the history of American literature. Other volumes in this set are ISBN(s): 0766194353, 141917665X.