Introduction

The collections of the AFA Library are arranged by two classification systems.  A library classification system is an ordering of the world of knowledge so that books of similar subjects can be kept together and have a unique shelf address (call number) as well.  The original classification system--the Dewey Decimal Classification--is a numeric ordering system.  The newer system--the Library of Congress Classification--is an alphanumeric system.

Regardless of the classification system used, each line of the call number of a book has a unique meaning:

• Line 1 of the call number usually refers to a specific subject
• Line 2 usually refers, by code, to the author
• Line 3 is a further differentiation, as required.  Sometimes Line 3 indicates a date identifying a particular edition of a work.