This book introduces students to the process of assigning and synthesizing the class numbers by the 19th edition of the Dewey Decimal Classification. The chapters and examples have been graded and no background experience has been assumed on the part of the reader. Aimed at the beginner, the book provides a complete course to train students in the techniques of subject analysis and number building involving the use of seven auxiliary tables and multiple synthesis. With many examples having been taken from 21st century literature, the book’s theory and bibliography have been updated to the latest 23rd edition (2011) with an appendix on the abridged edition (2012).