I just finished "Bury my Heart at Wounded Knee". This is essentially 500 pages of the Indians getting screwed repeatedly. If you haven't read it, I'd recommend you read 1491 first and get an idea of why the Indians were so outclassed by the Europeans in terms of population and military strength by the time the Whites encountered the Plains Indians. Its a sobering look at how an entirely defeated population was repeatedly kicked while they were down, and KNEW they had no choice but to take it or become extinct.
Read 1491 first, though, it definitely helps with perspective for "Bury my Heart".