James Ford Rhodes (18481927). History of the Civil War, 18611865 1917.
On the day before the attack (April 5) he telegraphed to Halleck: The main force of the enemy is at Corinth. I have scarcely the faintest idea of an attack (general one) being made upon us, but will be prepared should such a thing take place.1 At three oclock that afternoon, he said to a Colonel of Buells army, there will be no fight at Pittsburg Landing; we will have to go to Corinth where the rebels are fortified.2 At this hour Johnstons advanced corps was two miles from the Union camp and the rest of his 40,000 within supporting distance.3
William T. Sherman, who, in addition to his own division had general command of three others4 at Pittsburg Landing, was even more careless than Grant, for he was in close contact with the evidence; he had, however, received no order to throw up intrenchments, although Halleck had directed Grant to fortify his position. While the utility of hasty intrenchments on the field of battle was not yet appreciated,5 it is remarkable that with an enemy estimated at from 60,000 to 80,0006 and, located according to their own guess, not farther than twenty-three miles away, generals as resourceful as Grant and Sherman did not put their soldiers to work with the pick and spade. At a later period of the war, wrote Sherman, we could have rendered this position impregnable in one night.7