Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Interesting Idea, Poorly Developed

Leiber combines two interesting ideas, actually--the absolute impossibility of proving that other minds exist, and the mass-production of human minds in the modern world. Unfortunately, the story itself is full of coincidences, narrow escapes, and other melodramatics. And the explanation of how the few "alive" people can co-exist with the "dead" world is not very convincing.