Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A problem concept but well delivered

I think with "Building Harlequin's Moon" and "Ringworld's Children" Larry Niven has finally returned, putting behind him the horrid 1990s where he wrote one uninspired, confusing, and convoluted book after another. "Building Harlequin's Moon" is not on the same level as "Ringworld" or "The Mote In God's Eye," but it is a fine book and an enjoyable, quick read.As others have said, one of the things that holds the book back is the basic premise that only by creating a race of slaves, can the colonists save themselves. It doesn't ring true and nags at the back of your mind as you read the book. But putting this aside and going with the premise, we have great Niven characters on an interesting world. There is a point about a quarter of the way through the book when something is done to one of the main characters that just infuriates the reader. I knew when I got that mad, that I was hooked on "Building Harlequin's Moon."