On the first Tuesday of each month for the past year we’ve invited you and your homescholars to explore one of the major Dewey Decimal classes at your local library. Our survey for the year is finally done — hooray! — and if you’ve been following along with us, you’ve explored the whole of knowledge (!), from our Dewey introduction (September), to the General 000s (October), the Philosophical 100s (November), the Religious 200s (December), the Social 300s (January), the Linguistic 400s (February), the Scientific 500s (March), the Technological 600s (April), the Artistic 700s (May), the Literary 800s (June), and the Historical & Geographical 900s (July). Whew!
The Dewey system is the standard in American public libraries, and if your students are familiar with it they’ll be right at home in a small-town library near you and in a big-city library across the country — a lifetime of learning will be open to them.
But the Dewey system isn’t the world’s only library classification system. Most other countries have their own national systems that are suited to their local interests and their local collections (although some of these are modified versions of the Dewey system).
And there’s also one other big library classification system in use in the United States that your students will almost certainly encounter if they go off to college: the Library of Congress Classification system.
The Library of Congress is Washington is the largest library in the world, and we regularly recommend its online services to homeschoolers. At the beginning of the 20th century, when the Dewey Decimal Classification was coming into common use in most public libraries, Herbert Putnam (1861–1955), the Librarian of Congress at the time, wondered if LC could come up with something more suited to their own vast and ever-growing collections. The result was the Library of Congress Classification, which can accommodate deeper and broader collections more easily, and which is easier to expand than the Dewey system.
While the top level of the Dewey system is based on numbers — the 100s, the 200s, the 300s, and so on — the Library of Congress system is based on letters: Class A, Class B, Class C, Class D, and so on. (And you can see right away that it can have up to 26 top-level categories, instead of the ten that are available in Dewey.)
Most public libraries use the Dewey system, but most college and university libraries use the Library of Congress system. If you have a local university library near you, why not pay it a visit with your students and see how it is arranged. These are the main classes in the LC system:
- LIBRARY OF CONGRESS CLASSIFICATION
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- Class A – General Works
- Class B – Philosophy, Psychology, & Religion
- Class C – Auxiliary Sciences of History
- Class D – World History & History of Europe, Asia, Africa, Australia, New Zealand, etc.
- Class E – History of America
- Class F – Local History of the Americas
- Class G – Geography, Anthropology, & Recreation
- Class H – Social Sciences
- Class J – Political Science
- Class K – Law
- Class L – Education
- Class M – Music
- Class N – Fine Arts
- Class P – Language & Literature
- Class Q – Science
- Class R – Medicine
- Class S – Agriculture
- Class T – Technology
- Class U – Military Science
- Class V – Naval Science
- Class Z – Bibliography & Library Science
Just as the top-level Dewey classes are subdivided into “tens” — the 500s (Science) is subdivided into the 510s, the 520s, the 530s, and so on — the Library of Congress system creates first-level subdivisions by adding another letter: Class Q (Science) is subdivided into QA (Mathematics), QB (Astronomy), QC (Physics), QD (Chemistry), and so on.
Take out your copy of our recommended homeschool bird guide, the National Geographic Field Guide to the Birds of North America, and turn to the copyright page at the very end of the volume after the index. There in the fine print you’ll see all the publication details for the book, and as in most titles published today, you’ll also see recommended library call numbers. The recommended Dewey number shown is 598.297 (remember the 500s are Science and the 590s are Zoology), and right above that you’ll see the recommended Library of Congress number: QL681.F53. “Q” is Science, “QL” is Zoology (Animals), and all the numbers from QL670 to QL699 cover Birds.
Why not invite your students to be library detectives in your own home this week and see if they can find this “Cataloging-in-Publication” data in other books on your shelves. They’ll discover, for example, that your recommended homeschool dictionary is Dewey 423 and Library of Congress PE1628.
You and your students may never have occasion to use the Library of Congress system “in the wild” — Dewey is more than adequate for most general libraries — but if you do run across it, don’t panic. It’s just another arrangement, running from AA to ZZ instead of 000 to 999. The skills that your students develop learning Dewey will serve them well if they ever happen to encounter this alternative library “language.”
What delightful decimals have you discovered in your public library Hercules Term? Or, what lovely letters have you discovered thanks to the Library of Congress? 📖
❡ Dukedoms large enough: Have you found all the local libraries in your area? There may be more than you realize, and there’s no better homeschool field trip than a field trip to a new library! The WorldCat Library Finder will help you find all the library collections near you — public and private, large and small — and the WorldCat catalog itself will help you locate the closest copy of almost any book in the world. 🏛
❡ Dewey Detectives at home: Did you know there are secret Dewey Decimal numbers hiding in the books on your very own shelves? It’s true! Here are some tips on how you can send your students on a treasure hunt to find them. 🕵️♀️
❡ When in doubt, go to the library: This is one of our regular Homeschool Books & Libraries posts. Add your name to our weekly mailing list and get great homeschool teaching ideas delivered right to your mailbox all through the year. 🗞
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