This is the first scholarly history of the only regular army cavalry regiment raised during the Civil War. Unlike volunteer regiments raised by individual states, the regular regiments drew soldiers from across the country. By war's end 2,130 men and at least one woman from 29 states and 14 countries served in the 6th U.S. Cavalry. The regiment's initial cast of officers included two grandsons of a former president, a cousin of Confederate President Jefferson Davis, two cousins of the governor of Pennsylvania, the son of a Radical Republican senator who opposed President Lincoln, and a number of enlisted soldiers promoted from the ranks. The book relies heavily upon primary sources to tell the regiment's story in the words of the participants. These include diaries and letters of officers and enlisted soldiers alike, several of which are previously unpublished. Official reports are excerpted when appropriate to provide the commander's view of the regiment's performance.