Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Exciting and thought-provoking

As war rages throughout the galaxy, the bird-like Gubru invade the planet Garth, which is home to humans and their Uplifted client race, the chimpanzees. Cut off from outside help, two young people, one human and one alien, are forced by circumstance to become the leaders of a chimp army in a guerrilla war. There is a lot of action in this third novel of David Brin's Uplift series. So far, each entry has been better than its predeccesor. Brin's prose is frequently clunky, but his story is tight and he has a rare ability to create plausible and fascinating alien cultures and psychologies.