Western stories are usually monocultural or bicultural. By that I mean that in the first instance, the marshals, the cowboys, and the desperadoes all have similar backgrounds (more often than not, they're Scots-Irish transplants on the American frontier). In the second instance, authors write about the interaction between Westernized settlers and Native Americans.
Loren Estleman's casual mastery of the genre is such that in "White Desert," he's upped the ante by writing a multicultural western. You've got a familiar character, deputy U.S. marshal Page Murdock, but even he's more complicated than most of his two-dimensional forebears. Beyond that, Estlemen looks at the differences between America and Canada in the nineteenth century by having Montana-based Murdock work uneasily with the Royal Canadian Mounted Police. Then Estlemen adds aboriginal culture, but unlike most other writers of Westerns, he does not assign the Plains Indians to that role. Instead, he introduces Murdock (and us) to the Metis, chiefly via the guide whom Murdock hires to help him cross the unchartered northern prairies. Metis, it turns out, are French-speaking cousins to the more familiar Sioux, and they're ably represented here by three members of the du la Rochelle family. A Cree chief who was an actual historical figure also has a prominent impact on the narrative.
As if that weren't enough, Murdock also has reason to visit a colony of former slaves who left the United States to found a Canadian enclave they call Shulamite. Shulamite is led by a "Committee of Public Vigilance" and a voodoo practitioner who calls herself Queen Fidelity. Settlers there have a distincitve culture, too.
Watching Estlemen keep all the balls in play is great fun. Some of the violence in the book is almost shockingly graphic, and some of the language used by the bad guys is, too, but Estlemen never forgets that he's telling a story, and he does it very well indeed.