Lew Wallace of Indiana was a self-taught extraordinary military talent. With boldness and celerity, he advanced in less than a year from the rank of colonel of the 11th Indiana to that of major general commanding the 3rd Division at Shiloh. Ultimately, his civilian, amateur military status collided headlong with the professional military culture being assiduously cultivated by Maj. Gen. Henry W. Halleck, a cautious and difficult commander. The fallout was aggravated by...