cdb1d2e6__Metadata_Project___Confluence__Description
[Microdata tag] such as Book, Sculpture More specific types should be added to schema.org and have been suggested outside this effort. See this project for examples: http://www.essepuntato.it/lode/http:/purl.org/library/#d4e306 [Description] 
If search results could improve with most specific types, then use more specific type
Practical Properties Guide - Accessibility Metadata Project - Confluence
Description