Instruct: Classify an Amazon review into positive or negative sentiment.
Query: undoubtedly Tepper's best book

and an un(der)recognized classic of SF. Readers who have been put off by Tepper's more recent books, which I've found preachy and tendentious, should not let that scare them away from Grass. The book is concerned with some of the same issues that pervade her other fiction (gender and environmental themes, and more general ethical issues), but unlike in, say, Sideshow or Gibbon's Decline and Fall, the storytelling never founders under their weight. I read this book when it first came out and have read it at least 6 times since and never tired of it.