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 Cutrer provides the definitive edition of McClellan's detailed diary and letters from his service in the Mexican War.

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.