In this wonderful encyclopedia designed for middle- and high-school students, 341 entries explore the wonders of space. Each volume has a theme. Space Business (volume 1) covers topics such as Communications satellite industry, Law of space, and Space tourism. Planetary Science and Astronomy (volume 2) covers the more scientific aspects, including planetary explorations. Humans in Space (volume 3) treats manned missions and various astronauts, and Our Future in Space has entries for topics such as Asteroid mining, Mars bases, and Military uses of space. The entries in each volume are in alphabetical order and range from a single paragraph to several pages in length, with most being one or two pages long. The front and back matter are the same in each volume and include a few pages of reference tables such as conversion charts, time lines of milestones in space history and human achievements in space, a list of contributors, a table of contents for the set, and a glossary. Volume 1 has a unique time line of "Major Business Milestones in U.S. History. The index in the first three volumes is specific to the volume only, and there is a cumulative index in volume 4. Numerous sidebars provide additional information throughout the set. Words that appear in bold type in the entry are defined in the page margins and also in the glossary. The color illustrations and photographs are beautifully reproduced and appear on almost every two-page spread. Additionally, there are smaller portraits and black-and-white illustrations. Almost every person mentioned has a portrait somewhere in the set.The entries are well written and should be easily understood by the target audience of YA students. The breadth and depth of information will fascinate students and be very helpful in preparing reports and projects on a wide variety of space-related topics. School and public libraries should eagerly add this set to their collections.