About the OCLC Top 1000

The OCLC Top 1000 Web site presents the top 1,001 works most widely held by libraries, with thematic sublists, sample cover art, "Find in a Library" links, comparisons to other lists, and download files. A key to entries is available.

First published in the fall of 2004, the list has been updated for 2005. Because it reflects the decisions of many libraries over many years, the list would not be expected to change much from one year to the next. And, in fact, this year's list is substantially the same as last year's. What changes there are in individual rankings are due as much to continuing refinements in the list-building methodology as to changes in the system-wide collection actually held by libraries.

How do libraries choose?

Deciding what items to add to a library collection is part of what librarians call collection development. Libraries have written collection-development policies, which are based on the mission and goals of the library, the needs and requests of the community it serves, and the level of resources the library has to work with. Libraries also rely heavily on book reviews. A decision to purchase a single item is rarely made in isolation.

What does this list say about libraries?

Libraries are rich, deep, resources for preserving cultural heritage and indispensable resources for the communities they serve.

By and large the list reflects true classics and canonical works of western culture. The list also shows the extent that libraries strive to meet the needs of their readers, by offering books in high demand any given year. The list contains classic works such as the Bible, utilitarian works such as the U.S. Census and also popular works such as Tom Brokaw's Greatest Generation.

How the list was made:
WorldCat + FRBR + manual intervention + holdings + sorting

In a nutshell: we made a master list of all the items held by libraries around the globe. We tweaked it to bring together different printings and editions and translations, and then we counted the number of libraries that own each title. We ranked the titles in descending order by the number of items held by libraries. Then we provided some additional categories to create sublists of fiction, drama, children's works, and so forth.

Here's the detailed version of how the list was made:

The list is derived from WorldCat, a library catalog of items held by 53,000 libraries in 96 countries.

The records in WorldCat were machine-consolidated to bring together individual bibliographic records for different versions and editions.

The model for bringing records in a large bibliographic database together under one umbrella "work" is called FRBR (an acronym for Functional Requirements for Bibliographic Records), often pronounced "ferber" as in "ferberizing" a database.

OCLC Research developed an algorithm for machine-FRBRizing large databases, and our research team used this algorithm to create the list. (This algorithm is offered under an open source license from the OCLC Research web site.)

After FRBRizing WorldCat, we consolidated a few of the works manually, to make the list more appealing. For example, we consolidated all the Bible entries (New Testament, Old Testament, Pentateuch, etc.), and we brought together all the Census entries. We also threw a few titles out; typically uniform titles like " [selections]" which falsely yielded the semblance of a FRBR work. We anglicized titles where appropriate.

Then we counted the number of library holding symbols attached to the associated (FRBRized) bibliographic records, and ranked the works according to which titles are owned by the most libraries. We began our list with 494,901 WorldCat records; our goal was to end up with WorldCat's top 1000 works.

Finally, we classified the items in the top 1000 list to sort the fiction from the non-fiction, the drama from the poetry, and so forth. We classified our top 1000 list in 13 ways. These were casual judgment calls made by non-literary experts, and even so our decisions sparked many a mini-debate in the halls of OCLC. (Are musicals and operas both drama and music? What is "fiction," really? What exactly is a children's work?) You may well disagree with our sorting and classifying, but we hope you'll nevertheless have fun exploring the list.

By the way, we considered letting the MARC record arbitrate some of these disputes. In a FRBRized model, MARC was of little help because so many different editions were being brought under 1 umbrella.

Categories that we tried to provide, but which didn't make the final cut, include: Religion, Self-help, Pop Culture. We found these impossible to sort out.

Eager to borrow these?

We've supplied a button to check whether your nearest OCLC library has the item. Click down the list of associated ISBNs to see if any of them are in your library's catalog.

The button uses OCLC's xISBN technology coupled with OCLC's worldcat.org platform. It works best with Microsoft's Internet Explorer browser.

The fine print

We acknowledge that the OCLC Top 1000 list reflects some bias toward the cultural heritage of North America and especially the United States, and also toward English-language materials. This is because the number of OCLC member libraries outside the United States, and the resulting contribution of records and holdings to WorldCat, have considerable room for growth. Of the 53,000 OCLC member libraries, 9,357 are from outside North America.

This list was developed in mid 2005. Libraries keep up with the times and their collections change dynamically. So, too, would the real top 1000 works. Last year's list is still available for comparison, as a single web page showing the complete list, or as an Excel file (XLS:1.6MB/6sheets) which includes all sublist codes and the table of comparisons with other lists. This year's list also is available as an Excel file (XLS:1.4MB/6sheets).

Library workers with long memories may recall that OCLC Research published "Top 100" lists in the past. This list is different from its predecessors, in that the older lists had not been FRBRized, and were limited to 100 monographs or 100 serials.

Included here for convenient comparison are three earlier lists of "Top" items from WorldCat:

The OCLC Top 1000 list isn't perfect. We are a research team, and we continue to hone the technologies used to produce the list.


The OCLC Top 1000 list was created by OCLC Research. Shirley Hyatt, Larry Olszewski, and Jenny Toves developed the list, with help from Bob Bolander, Diane Morris, Lance Osborne, Cliff Snyder and Jeff Young.

In some cases we received permission to use art from the original publisher:

Suggestions, comments, questions?

We welcome hearing from you.