What Is an E-Book
An E-Book is a PDF and can be downloaded from your IMO Publishing account directly to your computer. You may have to fill in a purchase code, which can be found in your IMO Publishing Account.
One licence (read: 1 E-Book) gives you 2 "copies" to download on different devices if you wish, or use the second "copy" as a spare in case something happens to your device. But, most PDF books are not secured and can be shared among colleagues multiple times.
An E-Book works on a Windows Computer, a Mac Computer, and many smart devices (providing it has a "PDF reader" installed on it).
Click on the following link for more information about E-Books and E-Readers.