William Kossak (fl. c. 1860 - 1863) was born in Prussia and was apparently a refugee from the political turmoil that cut through the region in 1848. Upon outbreak of the American Civil War, Kossak immediately volunteered and received a commission as a Lieutenant in the 5th Missouri Infantry on May 20, 1861. By August he had earned a promotion to Captain and had been given the position of Additional Aide-de-Camp in the volunteer Engineers. He went on to serve on the staffs of the most celebrated generals of the western theater, including Grant and Sherman. Kossak participated in many campaigns during the war, including at Fort Henry, Fort Donelson, Shiloh, Corinth, Vicksburg, the Atlanta Campaign, and the March to the Sea. During most of this time Kossak reported directly to General Sherman and he earned personal commendations from both General Sherman and General Grant. He attained his highest position, Chief Engineer of the 17th Army Corps, during Sherman's campaigns in Georgia. Little is known about Kossak's life before or after his military service.