Instruct: Classify Amazon reviews into positive or negative sentiment
Query: The Ringworld is Unstable!

This the second on a series of three books. I do recommend you read Ringworld first. The main Character, Louis Wu, has been located and dissuaded by the ancient race of Piersons Puppeteers into returning to the Ringworld. But when they do, they discover someone has been altering the ancient order of things.Ringworld was basically a cliffhanger. Ringworld Engineers is an excellent continuation of this story!