Michael Shaara's The Killer Angels deals with what many would call the most important battle in American history—the Battle of Gettysburg—and makes it all personal. Shaara takes you right inside the minds of the officers on the field during the fight, giving you an up-close and deeply researched picture of the battle as it unfolded. More significantly, this novel helps explain why the war was fought, letting you see the central motivations of the characters and explore their ideas about what they were fighting for.

It's no wonder this baby won a Pulitzer Prize in 1974, the year it was published.

Originally, the Civil War was fought to keep the states together in one Union—at least, that was the stated goal. Abraham Lincoln, while he personally believed that slavery was wrong, said that he didn't intend to destroy slavery in the South; he just wanted to prevent its spread into new territories.

However, the goal of the war eventually changed to involve the actual abolition of slavery. After the Battle of Antietam in 1862, which was the second bloodiest battle of the war after Gettysburg, Lincoln issued the Emancipation Proclamation, saying that the slaves in the rebellious states were now "forever free." (The slaves in border states that were still loyal to the Union would later be freed with the passage of the Thirteenth Amendment.)

Now that the war really was about slavery, Gettysburg became the battle that would decide the fate of the South's "peculiar institution," as slavery was called back in the day. The Union hero Colonel Joshua L. Chamberlain—really the main character in The Killer Angels—represents the Northern, anti-slavery perspective in the book, but Shaara also lets us see what the Confederates believed they were fighting for—a way of life and a social order… even if it was all built on slavery. In fact, a sizeable part of the book takes us inside the heads of the two most important Confederate commanders—General Robert E. Lee and General James Longstreet, who both have complicated attitudes toward the war and the Confederate Cause.

The Killer Angels puts the central debate about the war front and center: was it a fight over slavery or a fight over "states' rights"? You get to see all the different perspectives, but in the end, one side seems to come out on top. If you know how the battle ended, you might be able to guess pretty easily…

"Killer Queen" is a song by the band Queen. The Killer Angels is an award-winning book by Michael Shaara. All confusion between the two should end right here.

While The Killer Angels shows us the tactics and the strategy of the Battle of Gettysburg and gives us special insight into the generals' decision-making over the course of three fateful days, the deeper question the book asks and answers is: "What was the Civil War all about?" If you live in the United States today, this is kind of an important question, since the Civil War totally remade American society, helping it become what it currently is.

It's possible that if the Confederacy had won a decisive battle at Gettysburg, the United States would now be two separate countries. But that didn't happen—and The Killer Angels is all about why it didn't happen. From the Confederacy's perspective, the events in the book unfold like a classical tragedy: Shaara charts General Lee's missteps as he attempts to direct the course of battle while struggling with ill health. The Southern Cause is overshadowed by a sense of impending doom.

On the other hand, the book also traces what a Union soldier would see as the triumph of freedom—the end of slavery and the birth of a new United States. What the Declaration of Independence promised—"Life, Liberty, and the Pursuit of Happiness"—suddenly comes much closer to being a reality for people of all races and creeds.

If you can understand what America was like at that time, you can understand what America is like now—though The Killer Angels probably won't help anyone understand things like Kim Kardashian and GoGurt. As William Faulkner put it, "The past is never dead. It's not even past."