This book can be used with multiple age ranges; elementary aged students can follow along with parental help, and middle school students can read and test their understanding independently; this book can also serve as a refresher course for Jr. High and High School students who focus on the "Explore More" questions at the end of the book. Each chapter review includes other "explore more" questions in addition to multiple-choice questions. Black and white photographs and diagrams, as well as reproduced ancient texts and materials on the night sky, are included. A cumulative review is also included in the back of the book. 173 pages, softcover, with answer key and index. Show Less