With The Confederate Cherokees: John Drew's Regiment of Mounted Rifles (Louisiana State University Press, 1988), author W. Craig Gaines produced both a regimental history and a fine capsule history of the deeply divided Cherokee Nation's role in the Civil War. At 125 pages of text, it's a short book, but it attempts broad coverage and description of military events is adequate. Gaines relates to the reader the violent factionalism that erupted among the Cherokees between the treaty (Watie) and anti-treaty (Ross) groups.
Much of the book centers on John Ross, a fascinating political chameleon, and his political faction, whose members comprised Drew's regiment. The men enlisted for a year, but never became a disciplined force and performed very poorly overall. Lukewarm Confederate supporters to begin with and generally unwilling to fight fellow Indians, most of the regiment deserted to the enemy in its first campaign in late 1861 against the pro-Union Indians led by the Creek leader Ophothleyaholo. However, the remnants of Drew's regiment reorganized in time for the Battle of Pea Ridge, where its military effectiveness was questionable at best. Later on, during the first Union invasion of the Indian Territory it completely dissolved, the men instead swelling the ranks of the Union 3rd Indian Home Guard regiment.
Although I would quibble with Gaines over a few things (mainly his version of Pea Ridge and the awful maps), The Confederate Cherokees remains a very useful historical overview. The rosters, organized alphabetically and included as appendices, further enchance the value of the book. Books like these really highlight the need for more modern attention to the Civil War in the Indian Territory. Beyond generalized societal disruption, the war inflicted serious loss in life and property for many different groups. Also, beyond the sustained popular obsession with pro-Confederate Cherokee leader Stand Watie, the men and units that served there are largely neglected. [A notable exception is David Haimerl's recent Clarkson's Battalion C.S.A. (reviewed here earlier)]. It would really be great if someone could update Britton and put together a new study of the Union Indian Brigade.