+44 (0) 1273 386849Your essential guide to cataloguing and classification, and why it matters
The hidden logic behind every well-organised library – and why it matters to your readers.
Managing a library can feel like learning a new language, especially without formal training. Even experienced librarians sometimes get caught up in the nuances of cataloguing, classification, and subject indexing.
Understanding these concepts is essential for keeping a library organised, whether you’re working in a school library, managing a law firm’s knowledge system, or curating a community collection. For other library and information-related definitions, download our glossary of terms!
What’s the difference between cataloguing and classification?
Historically called “cat & class” in library studies, these two essential skills form the backbone of information management. Although courses have changed and evolved over the past 20 years, they’re still taught in universities today, both as a standalone module or as an optional part of a wider information management degree.
- Cataloguing is all about recording bibliographic details, things like the book’s title, author, publisher, and ISBN. This is what tools like AutoCat do in a library management system (LMS).
- Classification is how books, journals and other materials are organised. Assign everything a shelfmark, classmark, or call number so that it can be easily located. For maximum end-user search flexibility, digital material can also be assigned a classmark – more on this below.
Example: Imagine you have a book on the legal battles over art theft in post-war Europe. Where should it go?
- In a law library, it might be classified under crime.
- In a public library, it could be placed under twentieth-century European art.
- In an art library, it might fall under art provenance and restitution.
- If it’s an online version, tag it as ebook and generate a link, subject to licencing conditions.
This flexibility in classification depends on the library’s focus and the judgement of the librarian or administrator managing the library catalogue system. However, as long as you are consistent and keep like-with-like items together, your users will enjoy searching and browsing through your collection.
What is the difference between classification, classmark, and class number?
Before we go any further, I want to define some words. In general library terminology, classification, class system, class number, classmark, shelfmark and call number all relate to the way books are organised on shelves. However, they have slightly different nuances:
- Classification is the broad term referring to the entire system used to organise materials, such as those mentioned above.
- Class system is another way of referring to the classification scheme in use.
- Class number refers to the numerical (or alphanumeric) code assigned to a book within a classification system.
- Classmark / shelfmark (UK) / call number (US) is the full identifier used to place an item on the shelf, which may include the class number plus additional details like author or location codes
Do you know what library classification systems are available?
How complicated – or easy – do you want your classification system? As mentioned above, libraries use different classification systems depending on their needs. Different libraries use different approaches:
- Dewey Decimal Classification (DDC) – Common in public and school libraries.
- Moys Legal Classification – Designed specifically for legal libraries.
- Library of Congress Classification (LCC) – Used widely in North American libraries.
- Custom Systems – Many specialist libraries create their own classification schemes.
Some libraries take unconventional approaches. The Warburg Library, for example, uses a system based on ‘the law of the good neighbour‘, where items with the same classmark are placed together, but not in strict order. This encourages serendipitous discovery during reader research.
For school libraries, a simple approach is recommended. Our guide on choosing a classification system provides practical tips.
How do publishers and the book industry deal with their stock? After all, it is in their interest that people can find what they want to buy! Go explore Thema, the subject category scheme for the global book trade, where you can find more information on the EDItEUR website. There is also information at the UK and Ireland Book Industry Communication (BIC), one of the many Thema National Groups.
What should my spine labels have on them?
Once a book is classified, it needs a spine label to ensure it’s shelved correctly. A typical spine label includes:
- Class number (e.g., 709.043, the Dewey number for twentieth-century European art).
- First three letters of the author’s surname (e.g., 709.043 DAV for David). This system ensures books remain in alphabetical order by author within the same classification.
- Optional location codes (e.g., 709.043 DAV MAI, with MAI an abbreviation for Main Section).
- Or even just a simple icon/image! 🎨
Some libraries use coloured labels to indicate different media types or locations. Avoid using unstable locations (e.g., “Bay 4, Shelf 3”), as these will change over time as your collection grows or changes.
What happens if your collection includes digital resources?
As we all know, library collections aren’t just about physical items on shelves. When setting up a library management system, your library catalogue should have fields for all formats and locations. I mentioned classmarks for digital content, however I can confirm that various national, public and academic libraries do not assign them. This depends on your library administrator’s preference.
Westminster library services, for example, use format labels like eBook, eJournal, electronic resource, eAudiobook, sound recording, and video to help users filter search results. Similarly, both the University of London and the British Library have a comprehensive list of formats and links to the online versions in their collections (access is subject to membership).
Examples for both location and format include:
- Encyclopaedia | Manchester | Reference Section
- Book | Main Library | Young Adult Section
- eJournal | Oxford University Press | Date
- eBook | Routledge | Date
- Computer File | Full Text Available | Date
Don’t forget to promote your digital collections to increase engagement. Depending on the type of reader, they may be comfortable checking online for items, but other people might automatically browse the hardcopy versions and miss the digital collection. Include shelf signage, posters, social media posts and a dedicated page on your website.
What’s the difference between subject indexing and taxonomy management:
Subject indexing and taxonomy management are often confused, but they serve distinct yet complementary roles in a library catalogue system:
Subject indexing involves assigning controlled vocabulary terms or keywords to materials, helping users find relevant resources through multiple search terms. This ensures consistency in searches and retrieval, even when different terminology is used.
Taxonomies are structured systems that define relationships between subjects, ensuring uniformity in tagging and categorisation across collections. They can range from simple controlled vocabularies to complex, hierarchical structures like thesauri and ontologies.
Legal libraries, for example, rely on various taxonomies:
- Moys Legal Classification structures legal materials within a broader classification system.
- Westlaw taxonomy categorises legal topics for research, ensuring better and more accurate search results.
- NosLegal, an open-source legal taxonomy, was recently updated to reflect practical experiences in taxonomy adoption and revision. Read on for more about NosLegal.
The evolution of NosLegal
Legal libraries and knowledge centres, in particular, rely on structured taxonomies to ensure consistency in research and document retrieval. One evolving example is NosLegal, an open-source legal taxonomy that continues to adapt to the needs of practitioners. NosLegal’s latest version restructures key facets, including:
- Legal specialisms – Now more refined to accommodate variations across legal systems and organisations.
- Work elements – Defined phases and deliverables for different legal tasks, initially covering Finance, Commercial Real Estate, and Disputes, with scope for expansion.
NosLegal remains a community-driven effort, encouraging feedback and adaptation. Law firms using this taxonomy benefit from an evolving, standardised approach to legal information organisation.
Final thoughts
In this post I mixed both theory and practice, but it is worth the effort when you can transform a chaotic collection into a well-organised, user-friendly library that everyone can use. Mastering cataloguing and classification ensure consistency. Clear and accurate spine labels ensure items are easy to locate.
Whether you’re managing a school library, law firm knowledge system, community library or private collection, getting these details right improves accessibility and usability. Are you struggling with library organisation? Let us know – we’d love to help!
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Frequently Asked Questions (FAQs):
1. What is the difference between cataloguing and classification in libraries?
Cataloguing involves recording bibliographic information about a resource (e.g. title, author, ISBN), while classification assigns a shelfmark or class number to place the item in a logical location within the library
2. Why is classification important in a library?
Classification ensures that related materials are grouped together, making it easier for users to browse and locate resources. It supports efficient shelving, search, and retrieval across physical and digital collections.
3. Which library classification systems are most commonly used?
The most widely used systems include:
Dewey Decimal Classification (DDC) – common in public and school libraries.
Library of Congress Classification (LCC) – used in academic and research libraries.
Moys Legal Classification – designed specifically for legal collections.
Custom Schemes – often used by specialist or private libraries.
4. What should a library spine label include?
A standard spine label typically includes:
The class number (e.g. 709.043 for 20th-century art),
The first three letters of the author’s surname,
Optional location codes or icons to support navigation.
5. Do digital library items need classification?
Digital resources don’t always require a physical classmark, but applying subject tags and format labels (e.g. eBook, eJournal) improves search and accessibility, especially within library management systems.
6. What is subject indexing in libraries?
Subject indexing is the process of assigning keywords or controlled vocabulary to describe the topics of a resource, helping users find content through keyword search and browse functions.
7. How does taxonomy management differ from subject indexing?
While subject indexing focuses on tagging individual items, taxonomy management creates a structured hierarchy or map of related subjects, ensuring consistency and discoverability across a collection.