What is the author's tone in The Cage by Ruth Minsky Sender?

The story is filled with despair and horror but has an undercurrent of hope that filters the despair. This is tightly bound with the will to live exhibited by many of the people in the story but is also tied to the fact that they were all giving, caring people. For example, while Riva was telling the story of her increasing illness that caused her to be bedridden for a significant period of time, she explained that she continued to work, braiding rugs.