Where the content of the eBook requires a specific layout, or contains maths or other special characters, the eBook will be available in PDF (PBK) format, which cannot be reflowed. Most VitalSource eBooks are available in a reflowable EPUB format which allows you to resize text to suit you and enables other accessibility features. System requirements for Bookshelf for PC, Mac, IOS and Android etc.Bookshelf Online Browser version support ».Learn More about VitalSource Bookshelf ».Offline Computer – Download Bookshelf software to your desktop so you can view your eBooks with or without Internet access.Mobile/eReaders – Download the Bookshelf mobile app at or from the iTunes or Android store to access your eBooks from your mobile device or eReader.The free VitalSource Bookshelf® application allows you to access to your eBooks whenever and wherever you choose. Routledge & CRC Press eBooks are available through VitalSource.