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.

• Metadata review dialog: Automatically insert series number when selecting a series from the completion dropdown. Also if the user does not specify a series number, use 1 as the default, instead of not setting the series.

• Fix regression that broke error reporting for save to disk for books that contain no formats.
• Metadata download: Fix metadata download not working for titles that contain a apostrophes in languages other than English.
• Fix deleting a book from both the library and the device causing the next selected book to be incorrect, when the library is sorted by the On Device column.
• FB2 Output: Fix generation of FB2 sections based on a multi-level Table of Contents in the input document.
• Tolino Shine driver: Fix option to swap main memory and SD card not working on OS X.
• FB2 Input: Workaround for broken FB2 files produced by convertonlinefree.com.
• OS X: Workaround for OS X installs that have incorrect permissions set on their home directories. calibre will now no longer refuse to start on such machines.
• MOBI Input: Dont crash on corrupted JPG images.
• Fix column icons not displaying for custom comments type columns
• Metadata review dialog: Show a confirmation for the 'Reject all remaining' button.