From 1865 to 1945, American literature entered an era of realism, naturalism, and modernism, reflecting the country's dramatic socio-political changes. This period, post-Civil War, saw the nation grappling with reconstruction, industrialization, and later, the Great Depression. Mark Twain was a central figure in this era, with works like 'The Adventures of Huckleberry Finn,' offering a frank critique of society through the lens of a young boy's adventures on the Mississippi River. Simultaneously, the literary movement of naturalism emerged, with authors such as Stephen Crane and Jack London depicting human beings' struggle against nature and social conditions. The early 20th century brought modernism, encapsulating a break with traditional forms. Poets like Robert Frost and novelists like F. Scott Fitzgerald and Ernest Hemingway used new techniques to reflect on contemporary life's complexity and disillusionment. This era also saw a bloom of diverse voices. The Harlem Renaissance, in particular, brought African American writers like Langston Hughes and Zora Neale Hurston into the spotlight, their works resonating with both racial pride and the desire for social and political equality. In this transformative era, American literature evolved, reflecting the rapidly changing society and diverse voices, making it a dynamic field that continues to resonate today.