Aldiko Book Reader is a great Android app to read EPUB and other ebook formats. The app has a slick and colorful interface. You can import your books and Aldiko organizes them on its bookshelf.
Aldiko Book Reader can be installed from here.
Formats supported: EPUB and PDF. I prefer using PDF Reader for PDF though, since it has more features that are useful for viewing that format.
To turn pages: Tap on right side to move to next page, tap on right side for previous page. You can also swipe anywhere on the display to move to next or previous page.
To change brightness: Aldiko sets its own brightness. Swipe up and down the left side of the display to change brightness.
Tap in center of display to get top and bottom bar: You can switch between day and night reading modes here. The night reading mode is excellent when you are reading with lights off.
The app does not point to any documentation. The user guide for Aldiko is here.
Tried with: Aldiko Book Reader 3.0.4, Android 4.4.2 and Moto G