Presents the basic concepts of this central element of the universe.
- ISBN10 0613763785
- ISBN13 9780613763783
- Publish Date 1 September 1998 (first published 1 January 1998)
- Publish Status Out of Print
- Out of Print 6 April 2021
- Imprint Turtleback Books
- Edition Turtleback School & Library ed.
- Format Hardcover (Library Binding)
- Language English