This is a sort-of alternate history of the period 1861-1918, written by a historian and economist, Roger L Ransom of the University of California Riverside. It is not a work of fiction, however, but a serious attempt to examine what might have happened had the Confederates won the war.
Ransom’s alternate history eventually has the war ending when the Union, stalemated in Virginia by Lee and a still-living Jackson, elects Horatio Seymour of New York President of the United States, superseding Lincoln.

The book contains two big surprises. One is that “a weakening demand in the international demand for cotton would lead to a decline in the price of slaves” as early as the 1870’s. “The growing economic pressures within the Confederacy to do away with alive assets would be strongly reinforced by political pressures from the international community for the Southerners to abandon slavery,” which they did following the 1880 election. While I am inclined to believe that slavery could not last forever, I am also inclined to believe that it would have lasted longer than 15 years from the end of the war to preserve it. I would have placed slavery’s demise some time in the early twentieth century.

The other surprise is the victory, in April1918, of the United States, an ally of Germany, against the British and Confederates, followed by the reunification of the country. I think that most people who are willing to play the what-if game would be willing to posit the USA allied with the British and the CSA allied with the Germans, or both of them allied with the British. ( )

A very interesting book but be aware this is not alternative history in the Harry Turtledove mold. This is more straight history with some speculation on what-might-have-been. The author looks at different turning points in the war and, if the South had won, what might have happened with it as a separate nation. ( )