This document summarizes 20 key figures from the American Civil War, providing a brief explanation of why each figure was important and which side they represented. Some of the most prominent figures mentioned include Abraham Lincoln, the Union president who opposed the expansion of slavery and led the Union to victory; Robert E. Lee, perhaps the greatest Confederate general who had early successes against the Union; and Ulysses S. Grant, a leading Union general who oversaw important victories that helped turn the tide of the war in the North's favor. Both Union and Confederate military leaders, politicians, activists, and others who played pivotal roles on both sides of the conflict are highlighted.