Library data has been designed to be read and interpreted by librarians and users. Although there are some controlled data fields, most of what is in the library catalog entry is text. The machine as user has not gotten a great deal of attention in the library cataloging environment. Now there's yet another potential user of library data, and that user is the Web and services that function on the Web. If we are to serve our users, then we need to deliver library services to users via the Web. But delivery over the network is not enough; our services must not only be on the Web, but need to be of the Web. With Web-based data, we can use the vast information resources there to enhance our data by creating relationships between library data and information resources. This will increase not only opportunities for users to discover the library and its resources, but also the value of the data by allowing its use in a wide variety of contexts.

The idea that library metadata will be used widely on the open Web changes the meaning of cataloging: cataloging will no longer be limited to the creation of records for the library catalog; the data will serve other functions as well, and users who may never directly make use of the library catalog. This is a true expansion of the role of library data, to the point where it can be used for any bibliographic function. However, the effort of cataloging need not increase: instead, the sharing of data can increase, and with some forethought the act of cataloging can draw on cooperative data sources. To be sure, redesign of cataloging systems will be needed.

There are four steps that must be taken in order to enter into the world of linked data: defining the data model, defining the data elements, defining the data vocabularies, and developing rules for data application. This issue of Library Technology Reports provides an explanation, using concrete models and real-world examples, of how to facilitate this transformation.

• Information Science
• Library Science