A review from the Roger Ebert people referred to Jon Krakauer's book as a "novel". It is not. It is non-fiction and historical.
I saw the first two episodes allotted so far. It is well-done, but there is an elephant in the room.
As I recall, the young wife (along with her baby) was murdered because she refused to participate in the polygamy on which the fundamentalist Mormons build their "church". Did the director and producers and writers remove this central plot point for some reason I cannot fathom? Will it come up in subsequent episodes?
Until then, I will grant that it is compelling, but not so much if you've read the book. As usual with films.