EBook readers are generally limited to specific digital format libraries. For example, the Kindle reader reads books in the so called AZW Amazon proprietary digital format . The Nook reader reads books in the EPUB format, (as does Google Play Books app), and also in PDF.
The Amazon format is derived from the older MOBI format. This format has been both optimized and protected where there is digital rights management, but proprietary. Files may need to be converted before they can be accessed generally.
The Kindle reader cannot read the EPUB format and the Nook reader cannot read the Amazon AZW format. However, other tablets can perform as Kindle or Nook or Google readers, using apps.
The widely used PDF format, is read on a tablet with a dedicated PDF reader application but can be displayed on the Kindle reader or Nook. Print size may or may not be satisfactorily adjustable, a serious drawback. The Nook Simple Touch handles text in PDF files elegantly without this limitation and with ease.
Because of the format limitations of various readers, conversion is often desirable between formats. The usual tool for conversion is a program for PCs called Calibre. Books are then transferred to reader or tablet, usually with a USB cable.
Tablets, however can receive books wirelessly and simply via a program called Airdroid. Airdroid connects easily and enables transfers of files from the PC.
Books may also be transmitted to tablets using email attachment or an app called Dropbox (also Google Drive) which provides a file which is accessible to other computers on which it is installed. Once saved on one computer, the file is available on the other(s).
Once the file is in the proper digital format and is loaded from the PC to the device, then a tablet can use a choice of reader apps. When the book filename is tapped the reader offers a selection of reader apps, each with its own unique capabilities. For example, an app may be used to read the book aloud.
Two such readers are Mantano and Moon.
Dictated and published with my Nexus 7.
(The Nook Simple Touch is worth having in addition to a tablet for its specific benefits in reading e-books and similar documents: small size, light weight, massive expandable storage, easy organization on shelve categories for easy access, readability in sunlight, non-glare, ability to read and format PDF files in its basic reader, and make the most of battery life..)
