The term 'eBook' simply means "electronic book," meant for viewing on your computer or other devices such as a Kindle or Nook.
Ebooks are usually in Adobe PDF format. All that is required to read an Ebook on your computer is a software program called Adobe Acrobat Reader, which opens PDF files.
Most computers already have the Adobe Acrobat reader software installed, but in the rare instance your computer may not have it, or if you need the latest version, you can download "Reader" for FREE at www.adobe.com.
EBooks in the PDF format are compatible with both the MAC and PC operating systems.