the last book I ever read (Rise to Greatness by David Von Drehle, excerpt seven)

from Rise to Greatness: Abraham Lincoln and America’s Most Perilous Year by David Von Drehle:

But as men fought over credit and blame, the larger meaning of Shiloh was written in the exhausted columns of mauled Confederates retreating through a pounding hailstorm, and in the Union lines too shattered and spent to pursue them. A strong Rebel force, fighting in its own heartland and on its own terms, had hammered a Union army yet failed to break it. And now, even as the Confederates made their way back to Corinth, additional manpower from the North was surging toward Pittsburg Landing: one the same day the Rebels were driven back from Shiloh, Pope’s army had finally captured Island No. 10. In short, the bluecoats were firmly lodged in Dixie, and they would not be driven out by head-on attacks. Johnston had landed his best punch, but it wasn’t enough.

Yet the ferocity of that blow was itself a grim turning point. A line had been crossed; on April 6 the splintered nation had entered an unspeakable realm. Total casualties were more than double the combined losses at Manassas, Wilson’s Creek, Fort Donelson, and Pea Ridge—all the major battles in the war thus far. Men saw things at Shiloh that prefigured the horrors of the war to come: entire forests sheared off by cannon fire; brains exposed in crushed foreheads; men holding their own entrails; fields furrowed by shell fragments and littered with muddy haversacks and broken rifles; acres strewn with dead and dying men and horses. One field was so thick with corpses, in Grant’s description, “that it would have been possible to walk across the clearing, in any direction, stepping on dead bodies, without a foot touching the ground.”