Metadata—even the word sounds hard to understand. meta comes from the Greek, and means “above” or “enclosing” Metadata is simply data about data.
In other words, metadata is information about your data. You can think of data as being an electronic document, file, music file, book or any other form content presented in electronic format. Metadata is meant to summarize the key characteristics of the underlying work—in our case, our books—for the purpose of making the work itself discoverable to electronic searches.