calibre is a free and open source e-book library management application developed by users of e-books for users of e-books.

New Features
New output format, HTMLZ which is a single HTML file with its associated images/stylesheets in a zipped up file
Useful when you want to convert your ebook into a single HTML file for easy editing. Note that this output plugin is still new and needs testing
When dealing with ZIP/RAR archives, use the file header rather than the file extension to detrmine the file type, when possible. This fixes the common case of CBZ files being actually cbr files and vice versa
Support for the Motorola Atrix
Allow the icons in the toolbar to be turned off completely via Preferences->Look & Feel When downloading metadata use the gzip transfer encoding when possible for a speedup.
Closes tickets: 749304 [External link]

Bug Fixes
Conversion pipeline: Workaround for bug in lxml that causes a massive mem leak on windows and OS X when the input document contains non ASCII CSS selectors.
Closes tickets: 754555 [External link]
Conversion pipeline: Handle inline