This is the first biography of Sherman's chief engineer and the man whose post-Civil War engineering work changed Great Lakes navigation forever. Orlando M. Poe chronicles the life of one of the most influential yet underrated and overlooked soldiers during the Civil War. After joining the Union Army in 1861, Poe commanded the 2nd Michigan Infantry in the Peninsula Campaign and led brigades at Second Bull Run and Fredericksburg. He was then sent west and became one of the Union heroes in the defense of Knoxville. Poe served under several of the war's greatest generals, including George McClellan and William T. Sherman, who appointed him chief engineer to oversee the burning of Atlanta and Sherman's March to the Sea. Though technically only a captain in the regular army at the war's end, Poe was one of Sherman's most valued subordinates, and he was ultimately appointed brevet brigadier general for his bravery and service. After the war, Poe supervised the design and construction of numerous Great Lakes lighthouses, all of which are still in service. He rejoined Sherman's staff in 1873 as engineer aide-de-camp and continued his role as trusted adviser until the general's retirement in 1884. Poe then returned to his adopted home in Detroit where he began planning his ultimate post-Civil War engineering achievement: the design and construction of what would become the largest shipping lock in the world at Sault St. Marie, Michigan. Mining an extensive collection of Poe's unpublished personal papers that span his entire civil and military career, and illustrating the narrative with many previously unpublished photographs, Paul Taylor brings to life for the first time the story of one of the nineteenth century's most overlooked war heroes.