Each novel and the entire series were written for the art of it. Sales are not a concern. These are serious works and not for the casual reader, who could in some cases struggle with it. The narrative, storyteller style harkens to an older era and is less common today. These books take a hard look at life in the Nineteenth Century through the eyes of a Native American and white who dare marry and attempt normal lives at a time when the former was a pariah in her own land. It is not about Indians (or whites) it is about these two people and those close to them . . . that's all. Similarly, each volume is not just a Western as the forth book, for example, includes multiple settings, with at least a third of the book set in the East.
The five book series is also not just a Western, with the final volume set almost entirely in the Philippine Islands. Similarly as well, the other five books are not light reading or an easy, rapid, action and conversation-filled romp. There is romance in these pages, real love, the kind people die for . . . . . and violence and mature themes. There is no graphic sex and gratuitous violence. That which is portrayed in a violent hard manner here is unfortunately historically correct.
The series includes five volumes. If you adjust and get through the slim first volume, happy reading.