Strange as it may sound, one of the major issues in setting up a library is how to arrange the books on the shelves. Most people want to be able to browse through books arranged by subject. To make that possible, the library has to decide what the main subject of each book is. For the sake of consistency, this is done using a standard classification system. This system is organized into 21 main classes which are designated by letters of the alphabet.
Expansion is possible by the addition of letters and numbers.
Each book is given a unique call number chosen according to the LC system, and the books are arranged on the shelves in order by that call number. The following call numbers are in order as you would find them on the shelf.