by John Keegan; Viking; 368 pages.

The first day of the Battle of Shiloh in the spring of 1862 ended with a third of the Union force dead, down, or fugitive and the exhausted survivors dreading the dawn that would see the Confederates push them into the Tennessee River. With the darkness came rain, and William Tecumseh Sherman found his commander, Ulysses Grant, standing out in it, chewing on the omnipresent cigar. “Well, Grant,” said Sherman, “we’ve had the devil’s own day, haven’t we.”

“Yes,” said Grant. “Lick ‘em tomorrow, though.”

And so he did. The victory was not, as John Keegan makes clear in his engrossing new military treatise, merely the result of the blunt optimism suggested by the remark, the simple doggedness to which some still attribute Grant’s successes. Rather, he finds in Grant, the “greatest general of the American civil war,” a keen intellect coupled with an uncanny ability to put himself in the mind of his opponent and the largest grasp of what it means to be a commander in a people’s war—the populist touch mirrored in Grant’s “ultimate readiness to command by consent rather than diktat.”

Grant is the third of four men Keegan has selected to show the progress of military leadership in various times; the others are Alexander the Great, the Duke of Wellington, and Adolf Hitler. Keegan not only conveys freshly and crisply the accomplishments of each of his subjects but uses their characters and careers to illuminate the cultures that shaped them.

Keegan’s prose is always lively. He retrieves Alexander’s personality from the mists of antiquity and suggests the scope of his accomplishment by positing a George Washington who, “having endured the long winter of Valley Forge and the setbacks of the middle years of the War of Independence, to exult at last in the capitulation of Yorktown, conceives the ambition of ridding all the Americas of foreign government. Imagine him embarking the Continental Army in the ships of the new-born United States Navy to voyage south, clear Mexico of Spanish troops, garrison the West Indies with Virginians or New Englanders and make a landing on the shores of South America. Then, victorious in Peru, he crosses the Andes, defeats the Spanish army of the east, and expires on the approaches to the empire of Brazil.”

For years senior lecturer at Sandhurst, Britain’s military academy, Keegan is capable of astringent tactical assessment: “For all their operational expertise, Lee and Jackson proved men of limited imagination. … Both thought in terms of defending the South’s frontiers rather than exhausting the enemy. The defeat of the Confederacy was in part the consequence of their essentially conventional outlook.” But he also has a sharp and humane interest in every other aspect of his subjects’ lives, so that we are treated to a comparison between the prose styles of Wellington (good) and Grant (great) and to a marvelous review of