The pivotal figure in American literature known for works such as "Huckleberry Finn" is Mark Twain. Twain, an influential author and humorist, explored themes of race, identity, and societal norms in his writing through vivid storytelling and complex characters. His work reflects the complexities of American life in the 19th century, particularly regarding issues of prejudice and morality. Twain remains a cornerstone of American literature.