William Y. Chalfant's book "Hancock's War: Conflict on the Southern Plains" is an interesting read, and certainly one of the most authoritative secondary accounts of that conflict. The author, a lawyer by training, does an excellent job scrutinizing the primary sources to determine a factual timeline of events - something difficult to achieve, given the conflicting sources of information on both sides of the conflict.
Among the few problems I had with Chalfant's work is that the author seems to think it necessary to remind the reader at every turn, and immediately after the quoting of a great many of the included Euro-American primary sources, that U.S. citizens and the U.S. Army were the invaders and the Cheyenne were only defending their land and way of life. While the Cheyenne certainly were defending their land and way of life, the constant nagging about that point becomes somewhat tiresome as the reader progresses throughout this lengthy book. The second problem that I have with this book is reflected in some of the smaller details. Chalfant refuses to address George A. Custer by his brevet rank (sometimes described as an honorary rank), but insists on addressing Indian Agents Leavenworth and Wynkoop by the title "Colonel," even though those were honorary titles for them. This makes it seem that the author has an axe to grind against Custer.
These shortcomings notwithstanding, Chalfant's book is exhaustively researched and detailed and is a valuable source of information on the conflict on the Southern Plains between 1867 and 1869. Custer enthusiasts will find a great deal of information about that officer and his initial experiences on the frontier, including the events leading to his court martial. Chalfant also does an excellent job outlining Cheyenne tribal structure and organization.
In short, Chalfant's book is a superior history of the subject - despite a somewhat biased approach, and it is well worth reading! Highly recommended!