FBReader is a popular eBook reader application that allows users to read various formats of digital books, including EPUB, MOBI, and PDF. It is available on multiple platforms, including Android, Windows, and Linux, making it accessible to a wide range of users. The app features a customizable interface, allowing readers to adjust font sizes, colors, and background settings for a personalized reading experience. In addition to its user-friendly design, FBReader supports online catalogs and can sync reading positions across devices. It also offers features like bookmarks, text search, and a built-in dictionary, enhancing the overall reading experience for users who enjoy digital literature.