The book opens with a present tense narration that sets the time, players, and place. It is mid-June of 1863. The Army of Northern Virginia is heading north behind the Blue Ridge Mountains, stealthily making its way to Pennsylvania. The Army of the Potomac is also moving, but slower, a characteristic that has plagued it for a long time.
The opposing armies are described, with information on their size, cultural makeup, beliefs, morale, and objectives. Major leaders are introduced, including Robert E. Lee, James Longstreet, George Meade, and Winfield Scott Hancock. Also, the setting is portrayed: hot rainy weather; men feasting on ripening cherries as they march and then suffering the after-effects of this diet; and areas deserted by the local population who suspect the coming conflict.
Shaara's style is to the point here, placing the reader clearly in the location and time of the story — right before one of the major battles of the Civil War. His use of the present tense, while differing from the rest of the novel, gives a sense of immediacy to the situation. It is like listening to a newscaster report live on an unfolding crisis.
The descriptions of the major leaders are like a news exposé. Using details from their professional backgrounds and bits of gossip from their private lives, Shaara works to build drama and create interest in the characters.
The description of the armies reveals their qualities, motivations, and stark differences. The Confederate Army is a united group. The men in it have similar backgrounds, religious beliefs, customs, and language. While they are mostly unpaid, many cannot read or write, and their physical situation is difficult at best — no shoes, worn uniforms, and not enough food — their morale is very high. This is due in no small part to their unified belief in what they are fighting for — disunity with the Union — and their faith in their leader. They view Robert E. Lee with the same reverence they have for their God, and they will follow Lee anywhere.
The Union Army is the opposite. They are a conglomeration of very un-unified men fighting for the unity of their country. They come from all walks of life, with different languages, nationalities, religions, and customs. They have seen mostly defeat, their morale is terrible, and they have no faith in their leadership, which changes often. Many are there for their own personal reasons.
One can feel in this introduction the increasing frustration in the ranks, and the desire for a definitive and final showdown. The two sides differ greatly in their makeup and morale, but one thing they both agree on: they want to settle things once and for all, right here and now, and go home. Without being told directly, the reader is aware that something powerful, ominous, and fateful is about to happen.