WTF is the Library of Congress Classification System?

What is the Library of Congress Classification System?

The Library of Congress Classification system (LCC) is a classification scheme that organizes books by discipline and subject categories. It consists of 21 basic classes, most of which are divided into subclasses. Each subclass contains a loose hierarchical arrangement of topics, starting with the general and drilling down to the specific. These topics have subtopics, which may be arranged hierarchically or alphabetically.

The Library of Congress Classification is an alphanumeric system. It uses letters to identify the basic classes and subclasses. LCC also uses Arabic numerals for further divisions.

Why is this important? Because the Library of Congress Classification system is how we locate books in libraries. It’s the basis of Library of Congress (LC) call numbers, which are alphanumeric notations assigned to each book. These notations give books a home on library shelves and tell us where to find them.

LCC also does wonders for browsing. Since the first part of a call number is an LCC notation, books in the same discipline with similar topics are shelved together for our convenience. To learn more about call numbers, see How to Find Books in the Library Using Call Numbers.

Who Uses the Library of Congress Classification System?

Academic and research libraries use the Library of Congress Classification system to organize their collections. Most public libraries, on the other hand, use the Dewey Decimal System. That’s why call numbers are wildly different depending on the type of library and classification system.

Origins of LCC

The Library of Congress Classification system was developed by none other than the Library of Congress! Duh.

Back when the United States was a wee country, Congress arranged its library by size. But by 1814, the library followed the Bacon d’Alembert system of classification, which had 18 broad categories.

Unfortunately, the Library of Congress burned down on August 24, 1814. The War of 1812 was raging on, and the British set fire to the unfinished U.S. Capitol, which housed the library’s 3,000 volumes.

Thomas Jefferson’s Library

Thomas Jefferson came to the rescue in 1815, selling his personal library to Congress as a replacement. For my history nerds out there, take a look at this letter from Thomas Jefferson to Samuel H. Smith, May 8, 1815, about transferring his library to Congress. Additionally, like every good librarian, Jefferson created a detailed inventory of his collection.

Anyway, Jefferson had arranged his library into 44 main classifications, which he based on the Bacon d’Alembert system. By the end of the 19^th century, however, the Library of Congress was growing and needed a more detailed classification system.

So, in the 1890s, the Library of Congress developed its own scheme based on Charles Cutter’s Expansive Classification.¹

Therefore, unlike the Dewey Decimal Classification system, the LCC began as a system for a specific collection.

How the Library of Congress Classification Works

Let’s take a look at the Library of Congress Classification system in action. We’ll review the 21 basic classes, the subclasses, and some topics.

21 Basic Classes

The 21 basic classes represent broad categories of knowledge. A single letter of the alphabet identifies each class. For example, B represents Philosophy, Psychology, Religion.

The basic classes are below, but you can explore the LCC in depth here.

Subclasses

Most of the 21 basic classes are further divided into subclasses. Each subclass is identified by 2 or 3 letter combinations. For example, BF represents Psychology while BQ represents Buddhism.

If you’d like a Totally Historic chart of the LCC subclasses, download this PDF.

Topics

Subclasses are divided into a loose hierarchical arrangement of topics. Each topic has a single number or a span of numbers up to 4 digits. Whole numbers can be extended into subtopics using decimals (take that, Dewey). 

Since there are so many topics and subtopics, I’ll give you an example.

• B – Philosophy, Psychology, Religion
  • BF – Psychology
  • BF1404-2055 – Occult Sciences
    • BF1444-1486 – Ghosts. Apparitions. Hauntings
    • BF1501-1562 – Demonology. Satanism. Possession
    • BF1562.5-1584 – Witchcraft
    • BF1585-1623 – Magic. Hermetics. Necromancy
    • BF1651-1729 – Astrology
    • BF1745-1779 – Oracles. Sibyls. Divinations
    • BF1783-1815 – Seers. Prophets. Prophecies
    • BF1845-1891 – Fortune-telling
    • BF2050-2055 – Human-alien encounters. Contact between humans and extraterrestrials

As you can see, the LCC system is a bit complex, but once you get the hang of it, it works wonders for organizing and browsing large academic collections. 

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Footnotes

1. Taylor and Joudrey, The Organization of Information. 78-79. ↩︎

Bibliography & Further Reading

*One of the following links is an Amazon affiliate link, which means I earn a small commission if you make a purchase, at no cost to you.

Library of Congress. “Library of Congress Classification Outline.”

Taylor, Arlene G., and Daniel N. Joudrey. The Organization of Information. 3rd ed. Library and Information Science Text Series. Libraries Unlimited, 2009. 78-79.