If you are developing a smartphone or handheld application, you can use DL Reader to quickly create a branded customized eReading app; or you could try RMSDK to build a more fully-customizable app.
DL Reader is a customizable EPUB and PDF eBook reading app for iOS and Android devices. It can be customized with your brand identity and tied to your ebookstore, enabling you to quickly and easily deploy a customized eBook viewer without any programming effort.
Learn more about the DL Reader.
The Adobe Reader Mobile SDK (RMSDK) is a programming toolkit which enables application developers to render PDF and EPUB content on their devices. It also supports Adobe's eBook content protection model and is compatible with the Adobe Content Server. The RMSDK has a much smaller footprint than the Adobe PDF Library SDK; consumes less power, and is generally optimized for use in handheld devices.
Learn more about the Adobe Mobile Reader SDK.