Sam"" is Sister Samantha, a Boston nun and trained nurse who sets out to establish the first hospital in the New Mexico Territory. Any novel in which the heroine feels ""seeds of discontent,"" ""inwardly rebels,"" yearns to deal ""with the flesh-and-blood reality of life and death,"" and swallows ""the bitter dregs of disappointment and fear"" all in a half-page is not off to a promising start. But the sheer tug of the incredible story surmounts the banalities. Sister Sam eventually discards the veil and ""weds"" the Apache Chief Mangus; she lives alone with him in the wilds, bears him a son, and sublimates her Irish pride into being the perfect squaw--but draws the line at hospitable wife-swapping. During her barbaric interlude the hermana (sister) becomes such a great White medicine woman, even for enemy tribes, that Chief Mangus at last commits a warrior's suicide to free her to work in the larger world. And--in the last few pages--Sam goes on to become the first woman M.D., to head an obstetrics college in Paris, to be published in six languages, before she has a reunion with her son in her old age. Effective escapism on the borderland of parody.