From Kovid Goyal
A one stop solution to all your e-book needs. It is free, open source and cross-platform in design and works well on Linux, OS X and Windows. calibre is meant to be a complete e-library solution and thus includes library management, format conversion, news feeds to ebook conversion, as well as e-book reader sync features and an integrated e-book viewer.
I come from the Unix world, which means calibre is architected in little pieces each with its own command line interface which means that each piece of functionality is reusable not just in python programs but in any software. In fact adding complete support for converting any new ebook format to calibre requires the writing of only two converters format->html and html->format as well as a metadata reading/writing tool. All the other features of calibre will work automatically with these three converters in place. Similarly, writing a device driver requires very little work. You basically have to implement a well-defined interface (interface.py). Once you do that, your device will have full support in calibre.
Adding support for new Input/Output formats
Calibre is written primarily in Python with a few C extension modules. So you have to contribute plugins in either Python or C/C++.
* Tag Browser: Support the creation of nested User Categories
* Disable Kent District Library plugin to download series information. The website could not handle the load calibre's 2 million users put on it. You can manually re-enable it if you really want series information, but it is very slow
* Drivers for the Wexler T7001, Archos 7, Wink and Xperia X10
* Comic Input: Add option to not add links to individual pages to the Table of Contents when converting CBC files
* EPUB Output: Try to ensure that the cover image always has an id='cover' to workaround Nook cover reading bug.
* ODT input: Update odfpy library to latest version, adds support for bookmarks
* EPUB Output: Remove unnecessary CSS page breaks as they confuse the latest release of iBooks
* Fix regression in 0.7.46 that broke creating date and composite custom columns
* Linux binary build: Fix ImageMagick trying to load system modules instead of bundled modules
* Kobo driver: Handle missing firmware version file
* ODT Input: Do not force the background color to white.
* MOBI Input: Do not speciy text-align for every paragraph. Fixes text-align inheritance issues for newer MOBIs with nested divs.
* EPUB Output: Do not set the file-as attribute on title elements in the OPF as the current OPF spec does not support file-as. Instead use a calibre extension to OPF.
* Content server: Fix regression that broke browsing User Categories via OPDS
* Update the book details panel after adding books incase automerge is turned on and the current book is affected
* FB2 Output: Fix paragraph spacing sometime incorrect.
* Tag Browser: Fix generation of search query for authors with quote characters in their names
* Fix bug that could cause download of cover/social metadata from Amazon to sometimes fail
* LRF Input: Workaround for broken LRF files from BookDesigner that have incomplete TextStyle elements
New news sources
* Flickr Blog by Ricardo Jurado
* Various Romanian news sources by Silviu Coatara
* Osnews.pl and SwiatKindle by Mori
* Roger Ebert Journal by Shane Erstad
Improved news sources
* Le Monde
* Ming Pao