In the first comprehensive biography of Halleck, Marszalek recreates the life of a man of enormous achievement who bungled his most important mission. Unable to produce victory for the Union forces, he saw his power become subsumed by Grant's emergent leadership, a loss that paved the way for Halleck's path to obscurity.

In the first comprehensive biography of President Lincoln's chief war advisor from 1862-1864, a prize-winning historian recreates the life of a man of enormous achievement who bungled his most important mission. Marszalek unearths the seeds of Halleck's fatal wartime indecisiveness in personality traits and health problems.