DJ : Short for dust jacket, a protective and often decorative wrapper, usually made of paper which wraps around the binding of a book.

spine : The outer portion of a book which covers the actual binding. The spine usually faces outward when a book is placed on a shelf. Also known as the back.

book club edition : A generic term denoting a book which was produced or distributed by one of any number of book club organizations. Usually the overall quality of the book's materials is lower than the same book as printed by a traditional publishing house.