In his standard reference work on the Civil War, Generals in Blue, Ezra Warner declared George B. McClellan (1826--1885) "one of the most controversial figures in American military history." In this revealing book, Thomas W. Cutrer provides the definitive edition of McClellan's detailed diary and letters from his service in the Mexican War (1846--1848), during which he began the rise that culminated in his being named general in chief of the Union forces and commander of the Army of the Potomac early in the Civil War. McClellan graduated second in his class from West Point in 1846 and served as a second lieutenant in Company A of the prestigious Corps of Engineers, the only formation of combat engineers in the United States Army. The company participated in Major General Winfield Scott's invasion of Mexico, playing a prominent role in the siege of Vera Cruz and the battles of Cerro Gordo, Churubusco, Molino del Rey, and Chapultepec and in the capture of Mexico City. Although only twenty-one years old at the war's end, McClellan earned brevet promotions to first lieutenant and then captain for his efforts. McClellan's colorful diary and frequent letters to his socially and politically prominent Philadelphia family provide a wealth of military details of the campaign, insights into the character of his fellow engineers -- including Robert E. Lee and P. G. T. Beauregard -- and accounts of the friction that arose between the professional soldiers and the officers and men of the volunteer regiments that made up Scott's command. A courageous, indefatigable, and superbly intelligent young man, McClellan formed close personal loyalties in those years. His diaries also reveal a man contemptuous of those he perceived as less talented than he, quick to see conspiracies where none existed, and eager to place upon others the blame for his own shortcomings and to take credit for actions performed by others. On the banks of the Rio Grande during his first weeks with the army, McClellan wrote in his diary: "I came down here with high hopes, with pleasing anticipations of distinction, of being in hard fought battles and acquiring a name and reputation as a stepping stone to a still greater eminence in some future and greater war." Carefully edited by Thomas W. Cutrer, these diary entries and letters do indeed trace McClellan's rapid development as a soldier and leader and put on full display the talent, ambition, and arrogance that characterized his career as general and politician.

George B. McClellan was a second lieutenant in the formation of combat engineers that accompanied Maj. Gen. Winfield Scott's army of invasion during the Mexican War (1846 -- 1848). His diary and correspondence written during this period records a rich record of the campaign and offers unique insights into the character of his fellow Engineers; the friction that arose between professional soldiers, officers and men of the volunteer regiments that made up Scott's command; and much about the character of "the young Napoleon," reflecting the talent, the ambition, and the arrogance that characterized the engineer, businessman, soldier, and future politician.

"McClellan is to me one of the mysteries of the war." - Ulysses S. Grant Over the last 150 years, historians and Americans have endlessly debated over the Civil War, including its causes and the best and worst generals. Nowhere has there been a sharper debate than over the career and legacy of George McClellan, with a majority viewing him as the North's biggest goat and a small but vocal minority insisting that McClellan was a very good general who was made a scapegoat by the Lincoln Administration and its supporters. Many members of the "McClellan Society" continue to assert that McClellan would have ended the war in 1862 without the Administration's interference. In 1861, McClellan was looked upon as a hero and even possibly a savior. Dubbed "The Young Napoleon," the 35 year old had been a prodigy at West Point, finishing in second place in the Academy's most famous class, the Class of 1846. After earning praise for his service in the Mexican-American War, McClellan had a short but successful career in the railroad industry and had been a foreign observer at the siege of Sevastopol.during the Crimean War. At the outbreak of the Civil War, there was no question that McClellan was one of the brightest and most experienced of the North's generals. Ultimately, of course, McClellan went from hero to goat, at least in the eyes of President Lincoln, who famously wrote that McClellan "has the slows." It was a sharp critique of McClellan's cautious movements, but McClellan was also faulted for conservative battlefield leadership in the Peninsula Campaign and at Antietam. McClellan also constantly overestimated his opponent's manpower, at times thinking the Confederates had double his Army of the Potomac when the exact opposite was the case. It was after Antietam and his bickering with the War Department over why he wasn't chasing Lee's battered Army of Northern Virginia that Lincoln finally sacked him, effectively ending his Civil War career. McClellan is best remembered for 1862, but he was also a Governor of New Jersey, Lincoln's opponent in the 1864 presidential election, and a writer seeking to reestablish his reputation before his untimely death.