Garrison Keillor reads Whitman's poem "The Cavalryman," written while Whitman served as a nurse during the US Civil War. John Stallworthy comments on the poem. Whitman, 1819-1892, was a groundbreaking U.S. poet, writer, teacher, journalist, and Civil War nurse. He is the author of Leaves of Grass. His poetry appears in the film Voices in Wartime.