Appointed by President Lincoln to command the Gulf Department in November 1862, Nathaniel Prentice Banks was given three assignments, one of which was to occupy some point in Texas. He was told that when he united his army with Grant’s, he would assume command of both. Banks, then, had the opportunity to become the leading general in the West—perhaps the most important general in the war. But he squandered what successes he had, never rendezvoused with Grant’s army, and ultimately orchestrated some of the greatest military blunders of the war. “Banks’s faults as a general,” writes author Stephen A. Dupree, “were legion.” The originality of Planting the Union Flag in Texas lies not just in the author’s description of the battles and campaigns Banks led, nor in his recognition of the character traits that underlay Banks’s decisions. Rather, it lies in how Dupree synthesizes his studies of Banks’s various actions during his tour of duty in and near Texas to help the reader understand them as a unified campaign. He skillfully weaves together Banks’s various attempts to gain Union control of Texas with his other activities and shines the light of Banks’s character on the resulting events to help explain both their potential and their shortcomings. In the end, readers will have a holistic understanding of Banks’s “appalling” failure to win Texas and may even be led to ask how the post–Civil War era might have been different had he been successful. This fine study will appeal to Civil War buffs and fans of military and Texas history.