FBReader (FBReaderJ) is an e-book reader. Supports epub, rtf, fb2(.zip), mobi, and plain text file formats.
FBReader is fast, highly customizable. Can use external TrueType/OpenType fonts. Includes hyphenation patterns for 16 languages.
Includes a browser/downloader for network e-book catalogs/stores. Several popular English, French, Russian, Chinese and Polish libraries are included. Custom OPDS catalogs are supported too.
Alternatively you can download books manually and put them into /sdcard/Books catalog on your device.
FBReader is integrated with external dictionaries. Supports ColorDict, all Slovoed dictionaries (by Paragon Software), Fora Dictionary, FreeDictionary.org, LEO dictionary.
Localized for 14 languages. Open-source (GPL).
Similar applications: Aldiko, Cool Reader, Moon+ Reader, Alreader