PDF Reader is free and optimized for Android devices.
One of the best document (Pdf fb2 DJVU etc.) viewer for Android.
PDF Reader allows you to customize the way you read on a per book basis: each document's layout can be tailored to give you the best reading experience and all settings will be remembered the next time you will open it.
PDF Reader supports the following PDF and document formats:
DjVU PDF XPS (OpenXPS) Fiction Book (fb2 and fb2.zip) Comics Book formats (cbr and cbz) plus - starting with version 2.0 - EPUB and RTF.

- Bookshelf view
- File Browser File Navigation
- Search text in book
- Night Mode
- Search all books (PDF DjVu) on device
- Full screen mode
- Light theme and black theme
- Bookmarks on page
- Epub3 format support
- User-created collections for sorting your books
- Easy navigation inside the book
- Search for text inside books
- 3rd-party (imported) book support

Disclaimer：
This app is base on PDFDroid code and licensed under the GNU General Public License.
GNU General Public License: http://www.gnu.org/licenses/