* Edgar Allan Poe (1809-1849): Poe is widely regarded as one of the masters of horror fiction and the detective story. His works often explored the themes of madness, death, and the supernatural. Some of his most famous works include "The Raven" (1845), "The Tell-Tale Heart" (1843), and "The Cask of Amontillado" (1846).
* Herman Melville (1819-1891): Melville is best known for his epic novel "Moby-Dick" (1851), which tells the story of Captain Ahab's obsession with hunting down the white whale. His works often explored the themes of good versus evil, the natural world, and the human condition.
* Henry David Thoreau (1817-1862): Thoreau was a philosopher, naturalist, and transcendentalist who is best known for his book "Walden" (1854), which recounts his experiences living in a cabin in the woods. His works often explored the themes of nature, self-reliance, and civil disobedience.
* Emily Dickinson (1830-1886): Dickinson was a prolific American poet who wrote over 1,800 poems, although only a few were published during her lifetime. Her poems are often characterized by their brevity, their use of slant rhyme, and their exploration of themes such as death, immortality, and the natural world.
* Walt Whitman (1819-1892): Whitman is considered one of the most influential poets in American literature. His poetry is often characterized by its free verse, its celebration of nature, and its embrace of the common man. Some of his most famous works include "Leaves of Grass" (1855), "Song of Myself" (1855), and "O Captain! My Captain!" (1865).
* Mark Twain (1835-1910): Twain was a humorist, journalist, and writer who is best known for his novels "The Adventures of Tom Sawyer" (1876) and "The Adventures of Huckleberry Finn" (1884). His works often satirized American society and celebrated the values of individualism and freedom.
* Louisa May Alcott (1832-1888): Alcott is best known for her novel "Little Women" (1868), which tells the story of four sisters living in New England during the Civil War. Her works often explored the themes of family, friendship, and female empowerment.
These are just a few examples of the many important American authors and poets who emerged during the mid-19th century. Their works have had a profound impact on American literature and culture, and continue to be read and enjoyed by readers around the world.