Renee Register & Thad McIlroy 
The Metadata Handbook : A Book Publisher’s Guide to Creating and Distributing Metadata for Print and Ebooks [PDF ebook] 
A Book Publisher’s Guide to Creating and Distributing Metadata for Print and Ebooks

The Metadata Handbook is a comprehensive guide for professional publishers, large and small, who need understand how metadata for books operates in the real world, and who need to implement a strategy to master the development and distribution of comprehensive metadata for the books they publish.

Its over 100 pages take the reader from metadata fundamentals through to the latest information on the use of ONIX 2.1 and 3.0. A comprehensive glossary simplifies numerous technical terms while a full listing of vendors and relevant industry organizations provides an annotated directory of resources available to publishers, including self-publishers.

This is the only published guide that shows publishers — including self-publishers — how to create metadata that makes their books discoverable online.