Yes it is the digital age, but that doesn't mean everything has to be digital. If you're Apple however, it should be your mission to at least offer everything in a digital format and that's pretty much what they do. One product which has been met with varying reviews is their iBook and a wide array of e-book reader options which seek to replace conventional textbooks.
Recently Apple released their second incarnation of the iBook, but textbook are still out ranking iPads and iBooks as an excepted form of learning text by a very large margin. Of course change doesn't happen overnight and there is certainly a lot more e-book readers available when compared with just a few years ago.
The subject of this next infographic from WorldWideLearn.Com is the popularity of iBooks and a cost comparison between the device and traditional texts. It's interesting what they found, and like I said, the numbers are changing everyday.