History of the Civil War, 1861–1865 is a book by American historian James Ford Rhodes, which won the Pulitzer Prize for History in 1918. The American Civil War was fought between the Union (North) and the Confederacy (South) with the primary cause being the status of slavery. At the time the war commenced, there were around four million enslaved black people, almost all of them in the South. Written at the height of World War I, this scholarly work on the war between the states is written almost entirely from the Northern perspective. Despite this, Rhodes lays out the facts of both sides and when his opinion is expressed, it is always declared as such. The book gives detailed portraits of the main leaders such as Ulysses S. Grant, and Robert E. Lee, as well as their actions both on the battlefield, and in the politics that were going on in Washington. The book also contains accounts of the major battles, and an insight into other factors that were affected by the war such as foreign economies and social concerns. The 1918 History winner in the Pulitzer Prize list.