Final answer:
Abraham Lincoln referred to Harriet Beecher Stowe's novel 'Uncle Tom's Cabin' as the book that started the American Civil War, due to its impact on the anti-slavery movement and intensifying sectional conflict.
Step-by-step explanation:
Abraham Lincoln referred to Harriet Beecher Stowe's novel Uncle Tom's Cabin as the book that "started this Great War." Stowe's influential work, published in 1852, exposed the harsh realities of slavery to the American public and historically, there are accounts that suggest Lincoln recognized the novel's impact on the issue of slavery, and, by extension, its contribution to the tensions leading up to the American Civil War. While not the sole cause of the war, Uncle Tom's Cabin energized anti-slavery forces in the North and provoked a strong defensive reaction in the South, further exacerbating sectional differences.