What are the differences between The Killer Angels and the actual Battle of Gettysburg?

Since author Michael Shaara went to great lengths to make his 1975 Pulitzer Prize-winning novel The Killer Angels as accurate as possible, coming up with actual differences between the book and the real Battle of Gettysburg are hard to come by. The novel is considered a work of fiction, and there are some examples that cannot be verified. Shaara creates much of the dialogue and mental introspection of the real characters from his own imagination since little of their actual thoughts and actions can be documented. For example, no one knows exactly what Robert E. Lee was thinking when he prepared his thoughts for the upcoming campaign.

However, Shaara did create one fictional character that he included among the real participants: Buster Kilrain. Kilrain was a former sergeant who was demoted to private and later died at the action on Little Round Top. Kilrain is supposedly based on another real figure, Sgt. George Buck of the 20th Maine. Singer Steve Earle also wrote a song based on the character of Kilrain, which was an abbreviation of Kil-ler An-gels.