science

Library of Congress Classification

Library of Congress Classification is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Library of Congress Classification rather than just read about it. In short: The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress in the United States, which can be used for shelving books in a library. LCC is used by many large research and academic libraries.

Key takeaways

Library of Congress Classification belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Library of Congress Classification to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Library of Congress Classification from memory before moving on to harder problems.

Reference excerpt

The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress in the United States, which can be used for shelving books in a library. LCC is used by many large research and academic libraries. LCC was developed in 1897 by James Hanson (chief of the Catalog Department), with assistance from Charles Martel while they were working at the Library of Congress. It was designed specifically for the purposes and collection of the Library of Congress, to replace the fixed location system developed by Thomas Jefferson. LCC has been criticized for lacking a sound theoretical basis; many of the classification decisions were driven by the practical needs of that library rather than epistemological considerations. Although it divides subjects into broad categories, it is essentially enumerative in nature. That is, it provides a guide to the books actually in one library's collections, not a classification of the world.

History The central core of the modern Library of Congress was formed from books sold to the government by Thomas Jefferson after the original collection was burned by the British in the War of 1812. As a result, the original classification system used by the library was of Jefferson's invention. However, by the end of the nineteenth century, the collection had grown to over a million volumes and his system was deemed too unwieldy. John Russell Young, the seventh Librarian of Congress, hired James Hanson and Charles Martel in 1897, who began the development of a new classification system that would more accurately describe the collections the library held. Young's tenure as Librarian ended with his death in 1899, and his successor, Herbert Putnam, continued to implement the updates to the catalog through his long stay in the office. By the time he departed from his post in 1939, all the classes except K (Law) were well developed. In creating their classification system, Hanson and Martel evaluated several systems already in existence, including the Dewey Decimal System, Charles Ammi Cutter's Cutter Expansive Classification, the Index Medicus, and the Putnam Classification System (developed while Putnam was head librarian at the Minneapolis Public Library). The one closest to their needs was Cutter's; however, he died before the completion of his system. Hanson and Martel thus decided to develop their own unique system, strongly based on his ideas. They published their first outline of the classification scheme in 1904. Development of the classes continued throughout the twentieth century. The last class to be developed was K (Law): the first K schedule was published in 1969 and not completed until the 2004 publication of KB. From 1996 onwards, the LCC schedules were available online, and since 2013, there have been no new print editions of the classification system. All updates are now distributed by the Library's Cataloging Distribution Service entirely online.

Design and organization LCC divides all knowledge into twenty-one basic classes, each given a single letter of the alphabet as an identifier. Most of these classes are divided further into two and three level sub-classes. With these sub-classes, numerical ranges are assigned to topics, going from more general to more specific. Unlike in the Dewey Decimal Classification, where the numbers assigned to a topic iterate throughout the system (e.g., the ".05" tag indicated a periodical publication on the topic), the LCC numerical ranges are strictly hierarchal, only corresponding to their level on the outline. LCC is enumerative, meaning that it lists all the classes in officially published schedules, which are updated as needed by the Library of Congress.

After the range of numbers making up the topical division, call numbers often also include one or more Cutter numbers, modeled after the unfinished Cutter Expansive Classification index. The full LCC schedules contain tables that describe Cutter numbers for certain types of media, collections of work, and geographical areas. Cutter numbers also can take the form of an author-specific code, containing a letter and several numbers corresponding to the author's last name. This serves to further distinguish publications and nominally alphabetize volumes within a topic section. The final component of a typical LCC call-number is the publication year, in full. Library collections can add modifiers to distinguish specific volumes, such as "Copy 1." LCC should not be confused with Library of Congress Control Numbers (LCCN), which are assigned to all books (and authors) and defines online catalog entries. Library of Congress Classification is also distinct from Library of Congress Subject Headings, the system of labels such as "Glaciers" and "Glaciers—Fiction" that describe contents systematically. One variation from the original LCC system is the National Library of Medicine classification system (NLM), which uses the initial letters W and QS–QZ, which are not used by LCC. Some libraries use NLM in conjunction with LCC, eschewing LCC's R, QM, and QP, which overlap with NLM's schema. Another is the Canadian Universities and the Canadian National Library using FC for Canadian History, a subclass that LCC has not officially adopted, but which it has agreed not to use for anything else.

Use and criticism

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Worked examples

Example 1 — a first encounter with Library of Congress Classification

Start with the simplest possible case. Write down what Library of Congress Classification claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Library of Congress Classification before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Library of Congress Classification ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Library of Congress Classification

In research: Library of Congress Classification appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Library of Congress Classification in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Library of Congress Classification is common in secondary-school and first-year university syllabi. It links to neighbouring topics Library of Congress Classification, so understanding it makes those chapters shorter.
In everyday life: Look for Library of Congress Classification outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Library of Congress Classification in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Library of Congress Classification means in your own words.
Compare your version with the excerpt and mark what you missed.
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Frequently asked questions

What is Library of Congress Classification in simple terms?

Why does Library of Congress Classification matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Library of Congress Classification?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Library of Congress Classification.