Major General Alfred Pleasonton (1824–97), though a major player in the Civil War, has until now never been the subject of a book, and though he’s the namesake of two U.S. cities, both misspell his name. Largely unknown today, Pleasonton exerted considerable influence on mid-nineteenth-century cavalry operations and was credited with saving the entire Army of the Potomac from disaster. A tireless self-promoter who used every possible connection to gain high rank, he allowed no one to come between him and his ambition. On several occasions he criticized foreign-born colleagues and subordinates, ruining the careers of highly educated, experienced officers.
Even so, Pleasonton had supporters at all levels of command. He was praised by army commanders, including George B. McClellan and Joseph Hooker, for his commitment to offensive warfare if not always for his intelligence-gathering skills. Although an inveterate army politician, Pleasonton did not hesitate to criticize superiors he thought lacking. When Ulysses S. Grant took over the Union armies in 1864, Pleasonton was exiled to the Trans-Mississippi Department. In that backwater theater he dealt Confederates invading Missouri and Kansas a series of dramatic defeats, but his career never revived. He retired from the army in 1867 to avoid serving under former subordinates. 
Despite his flaws and shortcomings—real and imagined—it remains fact that Pleasonton commanded the Cavalry Corps, Army of the Potomac, during a critical period of its service, when it transitioned from a punching bag for Stuart’s vaunted cavaliers to the most effective mounted command in any theater of the conflict. Edward G. Longacre makes a thorough and conscientious attempt to separate fact from fiction and truth from deception in Gettysburg Cavalry Commander.