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.

• Conversion: Add support for the CSS3 rem font size unit
• MTP devices, such as Android tablets/phones: Allow ignoring any folder on the device, not just top level folders. For newly connected devices, also scan /Android/data/com.amazon.kindle for books by default (newer versions of the Kindle app place downloaded files there).
• Speed up sorting when the book list is showing a restricted set of books, such as when the results of a search are displayed or a virtual library is used.

  Closes tickets: 1217622

• Edit metadata dialog: Add an undo option for the Trim cover button.

  Closes tickets: 1219227

• Amazon metadata download: Update to handle website changes at amazon.com
• PDF Output: Workaround a bug in the library calibre uses to render HTML to PDF that caused text in some documents that used small-caps fonts to not render correctly.

  Closes tickets: 1216354

• Kobo driver: When a sideloaded kepub is added from a Kobo device to the calibre library, it is added as an epub, but the file copied is corrupt.

  Closes tickets: 1221035

• Fix changing the user interface language in the welcome wizard causing some parts of the interface to remain in the old language until calibre is restarted.

  Closes tickets: 1220767

• Fix regression in 1.0 that broke setting author names with the | character in them.

  Closes tickets: 1220348

• Content server: When running from inside the main calibre program, do not restrict the books shown based on the current virtual library in the main program. If you wish to restrict the books shown in the content server, use Preferences->Sharing over the net.
• Output dates in the local timezone instead of UTC when generating CSV catalogs
• Library maintenance: When doing a check library instead of dumping the database to SQL and restoring it, run a VACUUM. This works around various bugs in the dump and restore capabilities of apsw.

  Closes tickets: 1217988

• Edit metadata dialog: Fix adding an image to an empty comments block not working
• Conversion: Fix font declarations with invalid font-family values causing conversion to abort when subsetting is enabled.
• MOBI Output: Fix conversion of some super/sub scripts failling if they are the first or last element in a paragraph.

  Closes tickets: 1218858

• New database backend: Various improvements to make the backend more robust against databases with invalid/corrupt data in them.

  Closes tickets: 1218465, 1218783

• Countryfile