What is a call number, and how do I use it to find books?
A call number is the address of the book, found on the white sticker on the book's spine. Just like your house has an address which can be used to find your house, we use the book's address - its call number - to find the book on the bookshelf.
A call number using the Library of Congress Classification System has way more information than you may be used to when using the Dewey Decimal Classification System at a public or K-12 library. So what does it all mean?
The first two lines of a call number are related to the subject of the book. In this example, DS 559.45 represents the Vietnamese Conflict. All books related to the history of the Vietnamese Conflict will start the same, and therefore will be grouped together on the same shelf. The labels on the end-caps of the bookcases correspond with these first two lines. For this book, look alphabetically on the labels for DS, and then for a number range that includes 559.45. Once in the correct aisle, you will first look alphabetically until you find DS, and then numerically until you find 559.45. Then you will look at the third line.
The third line also has a letter and a number. First find the letter alphabetically, then look for the number. Notice, though, this line starts with a decimal. You need to read the number as a decimal. Remember, when putting decimals in numerical order you compare one place value at a time. So, even though 9 is less than 12, 0.12 will come before 0.9 because 1 is less than 9. Some books may then have another line with a letter and number, just continue to match up one line at a time.
The last line of the call number has the publication year. This is great for comparing which book on a topic is the most recent.