The one caveat on that is it adresses slavery among Alaskan Natives and First Nations peoples in BC who are not Native Americans per this article title  Those enslaved by the Tlingit and Haida and Nuuchahnulth and Kwakwakawakw were often enough Coast Salish NativeAmerican peoples in the Puget Sound region howeverand I thinkthe book also discusses slavery of neighbouring groups such as the Chehalis by theChinookan peoples