I have just learned that Robert M. Utley passed away yesterday - June 7,2022.
Mr. Utley was a great historian of the American West, American Frontier, US Cavalry and Army of the West, Great Plains horse peoples etc.Sitting Bull of the Hunkpapa Lakota, Geronimo of the Chiricahua Apache, and George A. Custer of the US Cavalry were subjects of his studies.
The list of publication - books, introductions to books, articles and brochures, can be found here.
some Western American historic photos to accompany this sad posting -
some books can be read on archive - that is they can be borrowed there -