The most famous novel of the "Reconstruction Trilogy," based on the events in the US South following the end of the Civil War, "The Clansman" became the basis for the 1915 epic movie "Birth of a Nation." 

Using fictional characters, based on real personalities of the time (such as Augustus Stoneman, who is a personification of the real life Thaddeus Stevens), it tells of the tumultuous events following the assassination of Abraham Lincoln, whose death allowed the Reconstructionists to direct US internal policy in the South.

This in turn gave rise to much resentment in the South, and the book then follows the story of a Confederate Army veteran Ben Cameron, who, as part of the original Ku Klux Klan, is successful in overthrowing the Reconstruction regime.

The book was highly successful in its day, selling in the hundreds of thousands. As a play and as the film Birth of a Nation, it was seen by millions and officially endorsed by then US President Woodrow Wilson.

The other two volumes in this trilogy, "The Leopard's Spots" and "The Traitor," were equally as successful as "The Clansman."