What is the title of the two-volume biography written by Carl Sandburg?

The two-volume biography written by Carl Sandburg is titled "War Years and Prairie Years." This work is known for its comprehensive exploration of the life and presidency of Abraham Lincoln, combining extensive research and a narrative style that brings the historical context to life.

"War Years" focuses specifically on Lincoln's leadership during the Civil War, detailing the political, social, and personal challenges he faced in that tumultuous period. "Prairie Years" provides insight into Lincoln's early life in Illinois, reflecting on the formative experiences that shaped his character and political views. Sandburg's biography is significant not only for its depth but also for its literary qualities, bridging the gap between historical fact and engaging storytelling.

The other titles do not correspond to the two-volume biography in question. "Lincoln: The Great Emancipator" may refer to a work about Lincoln's role in the abolition of slavery but is not Sandburg's comprehensive biography. "The War of Independence" does not relate to Sandburg's work, and "Biography of a Nation" is too vague and does not align with the specific titles of his Lincoln biography. Thus, "War Years and Prairie Years" is the correct answer as it accurately identifies Sandburg's acclaimed work.