dc:Subject
A short description of the eBook.

attributes

id
Provides an element with a unique name within a single document. This is especially useful in works with extensive cross-referencing and linking, such as dictionaries, encyclopedias, or travel guides. Use of ids simplifies linking and updates.
xml:lang
xml language code.
xmlns:dc
Always equal to "http://purl.org/dc/elements/1.0/"

Sample:

See also:

<dc-metadata>