Did you wake up this morning with some 641.3373? Or perhaps you prefer 641.3372. Spend any time doing 643.7 or 746.46 this weekend?

We don’t usually have conversations in code at the Library, but we do love our Dewey Decimal call numbers as a way of organizing and finding books and other resources. To celebrate National Dewey Decimal System Day on December 10, librarians at Mid-Manhattan Library at 42nd Street posed for photos with some of their favorite call numbers.

As part of the celebration, I asked my colleagues what they would most like Library patrons to know about the Dewey classification system. Here are their answers! 
 

Our Top Observations about the Dewey Decimal Classification System

1. It’s designed for browsing.

Books and other materials are organized by subject, so if you’re looking for books about pets, visit the 636 section. If you’re looking for books about dogs, more specifically, go directly to 636.7. It you’re a cat person, your number is 636.8.

Books about U.S. history are shelved under 973—but in some branches like ours, that section is very large, so it helps to get a specific number with a decimal to narrow down the subject area. For example, books about the Civil War are shelved under 973.7. Books about the Obama presidency are shelved under 973.932.

You can search the Library catalog to find the call numbers you need or ask our staff for help. We do know some numbers off the top of our heads but, for others, we need to use the catalog, too. 

Please remember that the branch libraries use the Dewey Decimal System, but the research libraries use the Billings System, which is not browsable in the same way. If you’d like to learn more about how books are shelved in the research collection, check out this blog post on Billings classifications.

2. Items do not have unique call numbers.

Since the call number indicates the subject of the book, multiple books can be shelved under the same number. If you are looking for The Tipping Point by Malcolm Gladwell under 302 G (G for Gladwell), you might also find Social Problems by 19th century economist and philosopher Henry George, among other books.

The South Beach Diet by Arthur Agatston is shelved under 613.25 A, but so are many other diet and nutrition books by authors whose last names begin with A.

3. Call numbers are used across languages, ages, and media.

If you’re looking for books about fitness, they’re shelved under 613.7. Fitness books in Spanish are also shelved under 613.7, as are fitness books in Russian, Chinese, and so on. 

The call numbers in the library catalog and on the spines of the books indicate the language and the subject—SPA 613.7, CHI 613.7, etc.
The same call numbers are used in the children, teen, and adult nonfiction collections, so if you’re looking for books about dinosaurs, look under J 567.9 in the children’s section and 567.9 in the adult and teen nonfiction sections. (Children’s call numbers all begin with J for Juvenile).

We also use the same call numbers for nonfiction DVDs. So, if you want fitness DVDs, you'll look on the shelves under DVD 613.7, with yoga DVDs under 613.7046. If you want books about New York City history, visit 974.71, but guess where Ric Burns’s documentary series about New York City is shelved? Yes, it’s under DVD 974.71 N (N for New York, the first word in the title.)

How do the numbers work?

There are ten main Dewey classes or “centuries.”

And then each main class is divided into 10 sections or hundred divisions. Let’s look at the 600 class as an example:

600 Technology
610 Medicine & health
620 Engineering
630 Agriculture
640 Home & family management
650 Management & public relations
660 Chemical engineering
670 Manufacturing
680 Manufacture for specific uses
690 Construction of buildings

These hundred divisions are further subdivided into one thousand sections, which can be made even more specific with the addition of decimal points. For example, in the 640 section, Home & family management, you’ll find cookbooks - 641.5 (Charlene’s favorite) and Armand’s favorite, Home maintenance - 643.7; plus, books about sewing in 646.2, housekeeping (such as Marie Kondo’s blockbuster, The Life-changing Magic of Tidying Up) in 648, and childcare in 649.1.

The Dewey Decimal System has been revised many times since its introduction in 1876, and the current edition is the 23rd. Generations of catalogers have worked, and continue to work, to make the classifications and the subject heading language better reflect our evolving society.

What's in a number? Here are more of our Dewey Decimal favorites!

Jessica has always found it cute and charming that, in January, so much of the 395.22 section (wedding planning) is checked out of the Library because so many people get engaged over the holidays. 

It’s one example of how the Library is there for you at all stages of life with the resources you need.

In addition to 643.7 - Home maintenance and 004-006 - Computers, Armand really likes 385 - Railroad transportation.

Melissa (pictured above) also chose several numbers. Beyond 391.65, where you find body art and tattooing, and dinosaurs in 567.9, Melissa fondly remembers 650.14 (job seeking, resumes) as the first call number she was able to give to a library user without having to look it up.

Ricci picks 398.2 - Fairytales and folktales. We took this photo in the Children’s Room, where there’s a fantastic collection for kids… but keep in mind that we’ve got a huge folklore section for adults, too.

Several librarians looked to the 700 class for inspiration (Arts & Recreation). Lauren likes 746.46 - Quilting, with books on knitting and crocheting nearby in 746.43.

It wasn’t easy for Laura to choose just one section in the art collection, but the 759.972 section, where Latin American painters like Frida Kahlo (759.972 Kalh) and Wifredo Lam (759.9729 Lam) are shelved, really speaks to her.

Arieh, our photography maven, chose the 770 range - Photography, where he can find books on photographic equipment and techniques in 770 - 778 and works by photographers in 779. Liz recommends checking out 796.6 - Cycling to find bike books.  

It’s not surprising that many librarians chose numbers in the 800 class - Literature. In addition to bikes (796.6), Liz is a big fan of 811 - American poetry. Andrew chose 822.33 - Shakespeare, who has his own special subdivision of drama of the Elizabethan period, 1558-1625, and Emily chose a specific Shakespeare section for The Sonnets 822.33-Y7.

Wilsa’s favorite call number is 809 - History, description, critical appraisal of more than two literatures. It's a broad section but the main focus is on the written word or world literature, which she loves. 

Vilma loves the 860s - Spanish literature. Look for Neruda’s love poems in 861 Neruda, Lorca’s plays in 862 Lorca, books about Don Quixote under 863 Cervantes, and anthologies of Spanish literature under 868.

Mr. Chang is a fan of 895.11 - Chinese poetry. Remember how call numbers are used across languages? If you want to find translations of Spanish or Chinese poetry in English, look under 861 or 895.11 in the English nonfiction shelves. To find Spanish or Chinese poetry in the original language, look in the World Languages collection under SPA 861 or CHI 895.11.

Several of our librarians like to spend time in the 900s - History. In addition to Chinese literature, Mr Chang likes the 951 section - Chinese history. And Cynthia is not alone in loving the New York City history section in 974.71. It’s popular with readers and staff alike.

Travel books are also shelved in the 900s. Moriba likes to explore books and DVDs in 914 - 919.  She also recommends stopping by the 400s for some language-learning materials before a trip. Marianna thinks the 941.084 section, officially known as Great Britain- History- 1936-1945, is an interesting one. "This is where you would send a Winston Churchill devotee, who has read the the bios in Claudine's section," Marianna explains. "This man has his own call number in the history section, and he deserves it."

Claudine chooses B for Biographies. She thinks that reading about an individual’s life can bring things into perspective and provide valuable, even essential, life lessons—more than those found in many self-help books.

Why just a "B"? We don't usually assign decimal numbers to biographies and memoirs of individuals. Instead, they're shelved under B with the subject's last name and the first letter of the author's last name.

So, for example, you can look for Becoming by Michelle Obama under B Obama O. (But don't look for a while since there are more than 2,000 holds for the book right now!) 

Thanks to the staff at Mid-Manhattan who posed with, and shared, their favorite Dewey numbers!

What’s your number? Tell us in the comments section below.