Faceting is a special and useful feature provided by HT+Bookworm. It essentially allows the user to filter matches by publication place, genre, and more, based on metadata.
What makes HT+Bookworm a particularly interesting Bookworm is that the HathiTrust Corpus contains not only digitized volumes but also access to the metadata associated with these volumes. Since the HathiTrust Corpus consists of volumes from the world’s foremost research libraries, there is usually a considerable amount of metadata available with each volume, in the form of bibliographic records such as MARC (Machine Readable Cataloging Record) that have been carefully created by the library contributing the volume.
The presence of the bibliographic metadata can be very useful because it provides a way to look for trends at a finer level of granularity with faceted search. The values specified in the facet allows for a narrowly focused search to take place across carefully selected subsets.
You can facet, or refine, your search by clicking on the "Filter" icon in the box to the right of the search term.
Enter a term into one or more boxes to narrow your search and better meet your research needs. Note that these fields are only searchable by certain values that correlates to information that describes that volumes in the HathiTrust public domain collection. For example, you can only limit your search by "Publication Country" to countries with a corresponding volume in the collection. The search below is for volumes that contain the word Champaign published in Illinois.
Note also that you can select multiple values for any facet and the Bookworm will look for volumes that meets one or the other criteria. If you're familiar with Boolean searches, the search is completed with an "or" operator. For example, you could search for volumes published in either Illinois or Wisconsin, as seen below.
If multiple fields are used to facet the search, then the Bookworm searches for volumes that meet both criteria. This kind of search correlates to using "and" in a Boolean search. In the example below, the Bookworm will search for volumes classified under Language and Literature and published in Illinois.