Comets are no longer feared as harbingers of calamities. We now know that they are celestial bodies made up of dust, ice, and gas and that many of them follow a regular path through our solar system. The explanations in this nonfiction offering are easy to understand and accompanied by full-page, full-color illustrations. Each spread also contains a green fact box for the trivia buffs. There is a glossary and index and the words from the glossary are bolded and spelled phonetically in the body of the text. Part of the "Exploring Space" series, other titles include Black Holes, Our Solar System, Space Ships, Space Stations: Living and Working in Space, and Extraterrestrials: Is There Life in Outer Space?