calibre is a free and open source e-book library management application developed by users of e-books for users of e-books. It has a cornucopia of features divided into the following main categories:
Syncing to e-book reader devices
Downloading news from the web and converting it into e-book form
Comprehensive e-book viewer
Content server for online access to your book collection
Allow opening the full Tag Editor dialog directly from the book list by holding down the Shift key while starting an edit of a tag-like field. For example, click on the tags field for a book and press Shift-F2
Tag Browser: Allow undoing the deletion of items in the Manage categories window
calibredb add: Allow setting arbitrary identifiers, not just ISBN.
Add a 'Retry' button to the news download failed error message.
DOCX Output: Detect the common idiom of placing centered images as inline images inside a containing centered block and render the resulting image as a floating centered image in the DOCX file.
DOCX Output: Fix incorrect handling of bold/italic in paragraphs where the majority of text is either bold or italic instead of normal
Table of Contents editor: Fix save/load of settings in the XPath wizard not working across restarts
Get Books: Update the Kobo Store plugin for website changes