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: Add a new tool to manage fonts. Allows easily changing/removing/embedding fonts in the entire book. To use it go to Tools->Manage Fonts
• Edit Book: Allow the color of the links in the Live CSS panel to be themed.
• E-book viewer: Add a keyboard shortcut to bookmark current location.

• Edit Book: Check book: When auto-changing font name to match actual name in font file, also change the font name in shorthand font declarations
• Edit Book/Book polishing: Fix embedding all referenced fonts not catching fonts that are only specified via style attributes and not in any stylesheets.
• Conversion: Fix normalization of CSS shorthand font property not working when multiple font families are specified in the same shorthand property
• Edit Book: Live CSS: Fix clicking on link to go to style definition not working if the stylesheet contains CSS 3 @media queries or @font-face rules
• Edit Book: When importing DOCX files, set the media type for html files correctly
• Edit Book: Fix import of DOCX files that contain no Table of Contents not working.
• Portable installer: Fix a crash if the user selects a destination for the portable install that does not have enough disk space.
• Fix date column not showing date added when adding zip/rar files that contain an OPF with a calibre timestamp in its metadata
• Sony driver: Fix SONY annotation app not working with files sent to the device by calibre
• Linux build: Fix regression that caused opening PDF files (or any externally viewed files) preventing calibre from being restarted as long as the external viewer is not shutdown.
• Edit book: Fix changing underline style to none when creating a custom color scheme causes error.
• Check Book: Fix empty (zero byte) XML files causing check book to fail.
• Check Book: Fix combination of mismatching font family names and a font-family declaration with an invalid value (such as a dimension) causing auto fixing of errors to fail.