Description:After an historical review of the Classification, the author of this book describes and illustrates the changes that have been made to the 21st edition. The manual provides a review of how DDC is updated and gives detailed lists of such changes in each table and class. Examples and exercises assist the user in fully understanding the Classification's use, down to the book number. In addition, all changes that appear in the 20th Dewey and brief descriptions of their application are included to guide users in applying the Classification in the cataloguing process.