Calibre_server module allows you to expose Calibre library on a site made with Drupal.
Calibre is a free and open source application for managing a library of e-books. Provides a simple and efficient web server for searching and downloading e-books. Its integration with any web site can be made using iframes.
Integration by the Calibre Server module is another approach, based on direct access to the data stored by Calibre to generate views that allow you to navigate through the collection of e-books.
The advantage of this approach is a better integration with the look of the web site and resource consumption is lower because the Calibre server is not used.