The term next-generation catalog (NGC) first became omnipresent throughout the library industry with the founding of the NGC4Lib mailing list. Eric Lease Morgan of the University of Notre Dame founded the mailing list in order to create a channel for discussion on the topic of the next generation of library OPACs (online public access catalogs). Morgan noted four principles that define the NGC in a posting entitled “Next Generation Library Catalog.”¹ These four principles are the following:

• It is not a catalog.
• It avoids multiple databases.
• It is bent on providing services against search results.
• It is built using things open.

Library industry vendors and open source communities have provided solutions that appear to meet these needs—but as we further analyze the solutions, it is clear that they touch only the surface of these needs. It is clear that the NGC solutions that have been used in libraries fail these four principles. Let's take a closer look.

• Principle 1: It is not a catalog. A typical NGC solution is more than just a catalog—many of these products provide the ability to search more than just the bibliographic records from the ILS, such as digital collections produced by the institution or open-access data culled from open repositories. Some of these solutions have included the ability to harvest OAI-based repositories to include additional content in the index. However, this is still very siloed and narrowly focused. The NGC just blurs those boundaries making the distinction even more difficult for the general user. Because the solution expands the data set to include content from a few additional external sources, understanding the boundaries of this system is even more confusing for the user.
• Principle 2: It avoids multiple databases. While the NGC by and large has avoided multiple databases, many have incorporated federated search to provide a greater level of access. The NGC was thought of as the single-search-box paradigm that libraries have been dreaming of; however, federated search just exacerbated the problem by creating a less convenient and less simple interface—which was one of the key driving factors for the invention of the NGC. A single database is key to providing a simple interface, which brings us back to the failures in Principle 1. Many NGC solutions have attempted to be more than just a catalog by incorporating additional content, but in doing so have integrated federated search, thereby failing to meet Principle 2.
• Principle 3: It is bent on providing services against search results. Many NGC solutions have done very well with this principle. The interface and functionality have all been designed around working with the results set and providing services around it. For example, the incorporation of faceted navigation allows the user to modify results through the use of filters. Many NGC solutions provide recommendation functionality as well as the ability to share results in a more social environment and to expand the research to external entities such as Google Books or Wikipedia. Due to failures with Principles 1 and 2, these services are still fairly myopic—focused on the smaller collections represented within the NGC.
• Principle 4: It is built using things open. Here is another area where the NGC solutions have shone. Many have been built from open source technology and have incorporated functionality to include open-access content. Two solutions, VuFind and Blacklight, are available under an open source license, allowing them to be downloaded and installed at no cost. Of course, I am referring to direct financial cost and not staffing and resource cost—“free as in kitten, not beer.” Utilizing open source technology is a great way for the vendor of the product to reduce cost and build on a platform that other like organizations are also building on. For example, consider the widely popular Apache Solr and Apache Lucene, a search engine platform and an indexing engine respectively. These two open source products have become extremely popular in the library market and can be found in almost every product in the NGC market. As these technologies continue to evolve and get better, so will the solutions that are built around them. There has been one failure around this principle, however; the NGC has not facilitated the open sharing of content in a convenient manner. No NGC on the market today provides an open sharing process of MARC records. One open source solution, SOPAC, developed by John Blyberg of the Darien Public Library, has taken on the role of being a collaborative engine of social tags. One library with SOPAC can pool and share tags on records in its collections with other libraries that are using SOPAC. This is a great model that seems to have seen little adoption; however, a newer commercial product, BiblioCommons, seems to be trying to push this approach further. This concept of libraries sharing resources and services seems like a highly valuable proposition that deserves further research and investment. Lastly, while a typical NGC uses open content and open source software, it is not able to provide access to all of the vast collections of open-access content.

Figure 6, a diagram drawn by Morgan in 2006, depicts the architecture of a next-generation catalog. This diagram proves to still be very relevant today. However, there are three services that are missing from what is listed on the right-hand side to allow the NGC to better meet user expectations. These are recommend, browse, and relate.

Recommendations are becoming part and parcel of discovery systems. Amazon.com has been known for using this approach to help increase the visibility of its products and sales; similarly, libraries have been adopting this model to broaden the exposure of their collections. VuFind provides recommendations based on common elements.

In figure 7, we can see a view of the record for The Cathedral and the Bazaar—a popular book about open source software. On the right-hand side, we see similar items that are recommended to the user. Below that, the Other Editions box provides a link to the first edition of the book.

Browsing is also a highly valuable approach to website navigation, and the faceted navigation model makes that highly intuitive and greatly increases precision of the search results. Many sites that adopt the faceted navigation model, such as e-commerce sites like Bestbuy.com or Shopper.com, allow the user to start not by searching, but by browsing the collection starting from a list of facet values. If I am searching for a new television on the Best Buy website, for example, I start with TV & Video, then TVs, then LCD TVs (see figure 8). This path allows me to browse through the product line and get directly to what I am looking for. I don't have to think of search terms up front but am able to browse the taxonomy of terms in a hierarchical manner to find exactly what I want in a very intuitive way.

There is a growing need in the information industry to provide the ability to relate. With the advent of the Semantic Web, building relationships between entities will allow the researcher to understand more about the content that is being studied. Libraries have the ability to help the Semantic Web take shape. By participating in the Semantic Web and evolving cataloging practices, libraries can foster and define these relationships. A next-generation solution can be the tool that allows libraries to do this. The library catalog is an authoritative source on materials held by the library, and other sources are authoritative on subject terms, authors, and call numbers. When these connections are made, the researcher can be better equipped to browse at a more macroscopic level through this notion of the Semantic Web.

Morgan's assumptions from 2006 are quite visionary and depict a future that goes beyond the NGC. What Morgan has described is what is being adopted today by libraries as the next step in discovery and access, the web-scale discovery solution.