There are many different formats of e-books currently available, just as there are many different formats for image files (.jpg, .gif, .png, etc.) If you know the format of your e-book, you can find the proper device and/or software to view it with. Some of the most common are: .azw (Amazon Kindle), .kf8 (Kindle Fire), .iba (Apple iBook), .epub (Open source standard), .pdb (eReader), and .pdf (Adobe Portable Document Format).