I can't say it better than this first sentence
from WRAL in Chapel Hill:
Elizabeth Edwards, the political wife whose public battle with breast cancer, coping with marital infidelity and continued advocacy for the downtrodden raised her profile above that of her husband, died Tuesday.
Edwards had announced that she was in grave condition just yesterday, in this moving Facebook post:
The days of our lives, for all of us, are numbered. We know that. And yes, there are certainly times when we aren't able to muster as much strength and patience as we would like. It's called being human. But I have found that in the simple act of living with hope, and in the daily effort to have a positive impact in the world, the days I do have are made all the more meaningful and precious. And for that I am grateful.
Edwards had most recently authored two books on overcoming adversity in the ace of her cancer treatment and political career. She was first diagnosed with cancer in 2004.