The patent is—as valuable patents tend to be—both simple and extremely broad. The design patent merely covers the sequential animation of the frames show in the three figures, but makes no mention of what this animation applies to. So this patent is actually broader than just an eBook thing, although that's probably it's only use. On the other hand though, it should only apply to that specific animation, not others like it.
This is just a design patent, so it's not like Apple's ownership of this patent will keep other eReaders from providing functionality; it'll just keep them from looking like books while doing it. Or force them to simulate page turning from the top corner instead of the bottom. Granted, this isn't world shattering stuff, but it all seems pretty stupid. Is this really stuff that we need to be patenting? More here.