FBReader (FBReaderJ) is a free ebook reader.
Main ebook formats: ePub (including main features of ePub3), Kindle azw3 (mobipocket), fb2(.zip).
Other supported formats: RTF, doc (MS Word), html, plain text.
FBReader supports synchronization of your library and/or reading positions with the FBReader book network (https://books.fbreader.org/), a Google Drive™ based cloud service. Synchronization is disabled by default; to enable and configure it, use the preferences dialog.
FBReader is fast and highly customizable – it can use external TrueType/OpenType fonts and custom backgrounds, the screen brightness can be adjusted while reading (slide finger up/down along the left screen edge), and different day/night color schemes can be selected.
This reader also includes a browser/downloader to access different network ebook catalogs and stores. Several popular English, French, Russian, Chinese, and Polish libraries are included. Custom OPDS catalogs are supported too.
Varies with device