gen. henry halleck was one of the men most responsible for creating a professional U.S. army. he was an expert administrator and something of a renaissance man. he spoke fluent french and spanish, travelled widely, studied architecture, translated several books on napoleon's army, and enjoyed a reputation as an academic-type.

he commanded the union army in the west during the early years of the civil war and achieved a number of big victories while the union army in the east was still pinned down. but he was a cautious general, interested in careful administration of his troops, preferring a strong defense over a flashy offense. he was not present at any of his big military victories, so his rivals claimed he was more of a thinker than a doer.

as a college student he earned the nickname "old brains" because he did so well in his studies. the nickname would later become something of an insult based on his reputation for staying behind in the tent to plan strategy while other generals might have joined in the charge.

despite his impressive successes in the west, lincoln grew frustrated with halleck's intellectual nature. he wanted a commander who was more blood and guts. lincoln said halleck was basically just an administrator, not a fighter. he replaced halleck with gen. grant. (though halleck would later be a pallbearer at lincoln's funeral)

halleck served as grant's chief of staff and his skill at administration was key in securing many of grant's major victories.