Russell wrote the splendid The Sparrow and Children of God in the late '90s, and went on to win the Campbell Award for best new writer. Then she spent the next seven or so years researching and writing A Thread of Grace, a book about the Holocaust set against the background of the Italian resistance, 1943-1945.
The book works pretty well on many levels, but it is a little hard to follow. However, as you finish it you understand why she had so many characters and so many locales and why this is so important to the story.
Russell's ability to write completely haunting scenes is very much in evidence in this book. One near the end caused me to burst out crying in a public location and will stay with me for a very long time (luckily, I was alone and managed to pull myself together before anyone happened by).
I highly recommend this book, though it's a shame that the one scene set in 2007 probably isn't enough to to make it nominatable for the Hugo next year. However, no doubt that this book is much closer to history than to speculative fiction.