What is the author's tone in The Eichmann Trial by Deborah E. Lipstadt?

The overall tone of the story is one of hope against a backdrop of darkness, evil, and horror. The dark side of the story is that the crimes against the Jews happened at all. The hope appears as survivors tell their stories and one man - accused of being a high-ranking Nazi official who was overly zealous in his attempts to eradicate the Jews from Germany - is brought to justice.