Calibre is a free and open-source e-book management software that allows users to manage their e-books, convert between different e-book formats, and sync e-books with various devices. It was first released in 2006 and has since become one of the most popular e-book management tools available.

One of the most notable features of Calibre is its ability to organize e-books into different categories and add tags, making it easy to search and locate specific books. It also allows users to edit the metadata of their e-books, including the title, author, and cover image, and can even download missing metadata from online sources.

Calibre also provides a powerful e-book conversion tool, allowing users to convert e-books from one format to another, such as from EPUB to MOBI, or from PDF to EPUB. This is particularly useful for those who want to read e-books on different devices that may not support the same file format.

In addition, Calibre supports a wide range of e-book readers, including Amazon Kindle, Barnes & Noble Nook, and Kobo e-readers, and can automatically sync e-books with these devices. It can also connect to online e-book stores, such as Amazon and Google Books, allowing users to browse and purchase e-books directly from within the software.

Calibre is an essential tool for anyone who reads and manages e-books. Its powerful features and easy-to-use interface make it a must-have for anyone looking to organize, convert, and sync their e-book library.

Key Features:

• Library management system to organize e-book collection
• Format conversion for compatibility with different devices
• Built-in editor to modify e-book metadata and table of contents
• E-book viewer with customization options
• Integrated web browser for downloading e-books
• Synchronization options for keeping e-book collection up-to-date across devices
• Extensible with plugins to add additional features and functionality.

• Edit Book: A 'Live CSS' tool that shows all the style rules for the tag you are currently editing.
• Add an option to hide the book rating in the cover browser (Preferences->Look & Feel->Cover Browser).
• DOCX Input: if no language is defined in the metadata, use the language specified in the document default style.

• Edit book: Fix regression that sometimes caused incorrect syntax highlighting when non-breaking spaces/typographic hyphens are present in the text.
• Fix a regression that broke the compare books tool when used outside the book editor.
• Get Books: Update the Woblink plugin to handle changes to the Woblink website
• DOCX Input: Workaround buggy version of Microsoft Word converting newlines in the document summary into _x000d_. They are now ignored when reading metadata from docx files.
• Edit book: Fix Check Book failing if a binary file such as an image or font is mislabelled in the OPF as being a text file.
• OS X Build: Fix a bug that was preventing multiple instances of calibre being used by different user accounts on the same computer.
• Edit book: Dont show an error message when trying to use quick open with no book open
• Content server: Add .ibooks (note the trailing s) as an allowed format as well.
• Edit Book: Fix an error when running the Check Book tool on files with empty