How to Find Out Which Libraries Own Your Book

The fastest starting point is WorldCat, but the answer needs a footnote.

Here is the method. Search WorldCat by title and by each ISBN, record the OCLC number for every correct record, expand the holdings view, then open the local catalog of any system that reports a holding to see branches and copies. This guide is for an author whose book is already published and who wants a library number they can stand behind rather than a number that sounds good.

Here's how I found that out. In my outreach after No Loose Ends came out, I emailed 25 library systems, chosen for one reason: they were among the largest in the country. That is the whole sample. It is not a survey, and 25 of the biggest systems are not representative of the thousands of systems in the United States. One of them, in Chicago, wrote back to say they'd already bought twenty-six copies. I hadn't contacted them before that. They just bought it.

So the obvious next question was: who else? There are thousands of library systems in the country and I didn't have time to check each catalog. That's what WorldCat is for. I created a login, searched, and found ninety-two systems holding the book. Ninety-two. I was exceptionally surprised.

Then I learned the footnote. WorldCat shows holdings reported by participating libraries. It is useful evidence, but it is incomplete, can lag by months, and may count institutions or systems differently from branches. Do not treat it as a sales total or a complete adoption count. One title can also be split across several records for different editions and formats. If you want a number you can stand behind, search systematically, keep the records separate, and write the date next to the count.

What WorldCat is

WorldCat is a cooperative catalog run by OCLC. Libraries contribute bibliographic records and information about what they hold.

A WorldCat record can include the title and subtitle, author and contributors, publisher, publication date, format, edition, ISBN, subjects, the OCLC number, and the libraries reporting that they hold the item.

WorldCat isn't a retailer, a publisher dashboard, or a real-time inventory system. Think of it as the shared catalog card that thousands of libraries agreed to write on.

Step 1: Gather every identifier

Before searching, list every ISBN (hardcover, paperback, ebook, audiobook, large print, translations), any alternate publisher or imprint names, the exact title and subtitle, and any variants of your name.

If your book has several formats, one search result isn't enough.

Step 2: Search the title

Go to WorldCat.org (opens in a new tab) and search the exact title, in quotation marks where it helps. (When I did this, I needed a login to search. Interface details like that change, so don't be surprised if the front door looks different.)

Look for records matching your author name, publisher, publication year, format, language, and edition. Open each plausible record rather than assuming the first result is the canonical one.

Step 3: Search each ISBN

ISBN search is often the cleanest way to isolate a format. Search each ISBN with and without hyphens, and record which WorldCat result corresponds to which edition.

Build a table:

Don't add the counts together until you've checked for duplication.

Step 4: Record the OCLC number

The OCLC number identifies the WorldCat bibliographic record. It's different from the ISBN.

The way I keep them straight: the ISBN is the product's SKU, assigned by the publisher. The OCLC number is the serial number on the catalog card, assigned by WorldCat. One ISBN should ideally map to one correct record, but real-world records get duplicated, merged, and corrected.

Save the OCLC number. It makes future searching and correction work much easier.

Step 5: Expand the holdings view

On the book record, find the section showing copies at libraries. Set the location or distance wide enough to see more than nearby institutions. Sign-in requirements and interface wording change.

OCLC's current author guidance says to select the right item, find the library-copy section, broaden the distance, and view all libraries where available.

Official instructions: How to see which libraries hold a work (opens in a new tab)

Step 6: Check local catalogs

WorldCat tells you a system reports a holding. The library's own catalog usually tells you more: number of copies, branch locations, format, availability, holds, whether copies are checked out, and the local call number.

Search the library's catalog by ISBN and save the stable catalog URL where you can.

For a big system, a single WorldCat holding can mean many copies across many branches. Chicago's twenty-six copies were one line in WorldCat. A system count and a copy count aren't the same thing.

Step 7: Separate systems, branches, and copies

Use distinct measurements:

• WorldCat holding institutions: organizations reporting holdings on a WorldCat record
• Library systems: administrative systems that may contain several branches
• Branches: physical locations within a system
• Copies: individual cataloged items
• Available or checked-out copies: current circulation status, where public

Don't say "100 libraries own my book" when the data shows 100 copies at 30 systems, or 100 WorldCat holdings spread across four editions.

I'm a lawyer, so this is where my day job shows. I'd rather say "92 systems as of September" and be able to prove it than say "hundreds of libraries" and hope nobody checks. The honest version is usually more impressive anyway, because it comes with receipts.

Why a library may be missing from WorldCat

OCLC lists several reasons. The library isn't an OCLC member. It hasn't added or exposed the holding. It cataloged a different edition. It doesn't maintain the subscription or setting needed to display the holding publicly. Or the record simply hasn't updated yet.

So describe WorldCat numbers as reported holdings, not a complete census.

Official explanation: Why a library may not display as owning a work (opens in a new tab)

What if the book isn't in WorldCat?

You can't upload a title to WorldCat yourself.

OCLC recommends contacting an OCLC member library and asking whether it can catalog the work. The library decides whether to acquire and catalog the book. Accurate metadata, an ISBN, professional production, and normal library distribution all make that decision easier.

Official explanation: How a work can be added to WorldCat (opens in a new tab)

What if the WorldCat record is wrong?

You can't edit the record, and nobody can promise you a change. What you can do is take the right route for the error.

1. Confirm you're looking at the right edition, and write down its OCLC number so everyone is talking about the same record.
2. Document the specific factual error with evidence: a copyright-page scan, the publisher page, the correct ISBN record, the cover, the publication date, contributor information, or the edition statement.
3. Read OCLC's current guidance for authors. It says to contact the publisher or the institution that owns the work first, because those sources supply much of the metadata in WorldCat and are often the only ones able to edit it.
4. If the wrong detail came from commercial metadata (title, subtitle, contributors, format, publication date, publisher), fix it upstream with the publisher, distributor, or platform that sends the feed. Fixing it there is also what stops it coming back.
5. If the problem is in the library record itself, ask the cataloging staff at a library that holds the book to report it, following the route OCLC's guidance specifies. Give them the OCLC number and say exactly what is wrong.

OCLC also maintains channels for reporting corrections for eligible record-change types.

Official guidance: Requesting a change to a WorldCat record (opens in a new tab)

How often to check

Publication month, then 30 days and 90 days after. Monthly while you're actively doing library outreach. Quarterly after the first campaign. And whenever a new format or edition appears.

Record the date with every count. Holdings change, and a number without a date is a rumor.

Can you use the numbers publicly?

Yes, if you describe what you actually counted and link to the supporting records where appropriate.

Good examples:

• "The hardcover is held by more than 40 institutions reporting through WorldCat as of [date]."
• "The city library system lists 12 copies across its branches as of [date]."
• "Six copies were checked out when we checked the public catalog on [date]."

Avoid calling institutions "public libraries" without checking their type, combining editions without saying so, treating a branch as a separate system, presenting today's checkout status as a permanent statistic, or implying WorldCat includes every library.

What the numbers can teach you

Holdings aren't just a vanity metric. They can show where the book is gaining traction, which formats libraries prefer, and whether the catalog records are split or wrong. They can also help you decide which comparable library systems are worth approaching next.

The Chicago reply changed how I approached every library after it. Use what you find the same way.

Frequently asked questions

Is WorldCat free to search?

WorldCat.org provides public search access. Some features, holdings views, or institutional services may require sign-in or library access.

Does a WorldCat holding equal one copy?

No. One holding institution may own multiple copies across several branches.

Can WorldCat show whether the book is checked out?

The local library catalog may show current availability. WorldCat itself may route you to the local catalog. Availability changes constantly.

Why does my book have more than one WorldCat record?

The records may represent different formats, editions, languages, publishers, or duplicates. Compare the ISBN and publication details.

Can I correct WorldCat myself?

You generally can't edit the catalog record directly. Report the specific error through OCLC's process or work with a holding member library.

Keep a reliable holdings record

Use the free Libraries checklist, or create a free Author Profile and add your book, one payment, to keep the work in one place.

Sources

• WorldCat (opens in a new tab)
• OCLC information for authors (opens in a new tab)
• How to see which libraries hold a work (opens in a new tab)
• How to add a work to WorldCat (opens in a new tab)
• How to request a record correction (opens in a new tab)