I think the greatest fiction writer of all time was Mark Twain. Although he did write other novels, The Adventures of Tom Sawyer and the Adventures of Huckleberry Finn will remain as some of the most important and influential American novels of all time. Mark Twain wrote fiction, but his writing was about more than entertainment. His stories told about the state of civil rights at the time. Mark Twain was an abolitionist and spoke out against slavery.
His stories also spoke of religion and labor rights. Mark Twain was an imperialist and later in life an anti-imperialist. Mark Twain's writing are important not only because they are brilliant but because they speak of the times in which he wrote.