Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Very informative and readable

This is an excellent and up-to-date book about galactic astronomy that can be read by just about any interested person. It has an enormous amount of descriptive material about galactic anatomy, the Milky Way Galaxy, the Magellenic Clouds, the Local Group, Clusters, and Superclusters. It discusses the problem of the "missing mass," and of galactic origin and evolution. There's an introduction to interacting and starburst galaxies, to ultra-luminous infrared galaxies, to radio galaxies, Seyfert galaxies, Gamma-ray bursters, and Quasars. All in all, it is an easy way to learn a great deal about the subject: it has more meat than most books for the layman but is easy to understand.