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All Things eBook: The Basics

This all-purpose guide to all things ebook assumes no prior technical knowledge of the subject and includes the ground-level basics.

What is an eBook?

An electronic book (also e-book, eBook, digital book) is a text and image-based, book-length publication in digital form designed to be read on computers or other digital devices.


  • One type of eBook is specifically designed to be downloaded and read on a variety of digital devices, such as an eBook reader.
  • Another type of eBook is browser or web-based, which means that it is designed to be read online and typically cannot be downloaded to a PC or other digital device.

What other digital devices allow you to download and read eBooks on them?

other mobile or pocket-sized computing devices that typically have a display screen with touch input or a miniature keyboard include: 

  • Smartphones  
  • iPod Touch
  • Tablets - portable pcs equipped with a touchscreen that may be pocket-sized like a smartphone or medium-screen-sized like the iPad.


App is an abbreviation for "application" (i.e., software application). 

It commonly refers to a small, specialized program that can be downloaded and run on your computer or mobile devices (smartphones, tablets, etc.) 

  • eBook apps: allow you to download and read proprietary formats on a variety of devices. 

What is an eBook reader?

An eBook reader, also called an e-book device or eReader, is a handheld or mobile electronic device that is designed especially for the purpose of reading eBooks and periodicals.

  • eReaders are designed for portability, readability, and battery life.
  • A single eBook reader can hold thousands of texts.
  • Many eReaders employ electronic paper technology, or E-Ink, to display content. This feature reduces eye strain and makes the text more readable in bright light. 
  • eReaders allow users to download eBooks onto them in a couple of major ways:   
    eBooks can be downloaded to a PC and then transferred through a USB cable to an eBook reader.


  • some eBook readers include some form of wireless internet connection and sometimes have a relationship to a digital eBook seller, allowing the user to buy and receive eBooks through this seller without needing access to a PC. Increasingly, public libraries lend eBooks purchased and distributed through a third-party vendor (e.g., OverDrive) that has agreements with eBook publishers and sellers (e.g., 


Examples of popular eReaders include:

the Amazon Kindle


the Barnes and Noble Nook


the Kobo eReader


eBook File Formats and Digital Rights Management (DRM)

eBooks have two different types of format:

file format and DRM format

A file format is the way that information is encoded for storage in a computer file. There are two main categories of file format: proprietary and open.

Proprietary eBook file formats are designed by eReader manufacturers to be unique to that manufacturer's eReader (e.g., Amazon Kindle). 

Open, or general, file formats, such as EPUB, PDF, TXT are designed so that most eReaders can view them. 

Common file formats:

Format               File Extension

EPUB                      .epub

Kindle                     .azw

PDF                        .pdf

Microsoft Reader       .lit

MobiPocket              .prc. .mobi

Plain Text                .txt

HTML                      .html

Digital Rights Managment(DRM) is "access control technology" that companies (hardware manufacturers, publishers, copyright holders) put on eBooks and other digital products to limit the use of digital content and devices after sale.

DRM acts as a lock on eBooks to prevent buyers from copying them, passing them on for free, or reading them on a competitor's eReader.

For more information:

eBook formats

Comparison of eBook formats

eBook filetype and DRM

Digital Rights Management (DRM)

Need one-on-one Research Assistance?

 The Greenville County Library System's 

Book a Librarian

service connects library cardholders to one-on-one research assistance, help with eBooks and other downloadables, and technology training.


  • eBooks are available through OverDrive for registered borrowers of the Greenville County Library System who are Greenville County residents.
  • OverDrive provides the Greenville County Library System with a portal for browsing, checking out, and downloading eBooks in EPUB, Kindle, and PDF formats. OverDrive supports iPod®, iPhone®, iPad™, Android™, Amazon Kindle®, Sony® Reader, and thousands of other mobile devices.