Author seems to me to mainly focus on the gestures of an interface. I'm not a big fan of greasy fingered swiping on a tablet or phone. I'll use it if I have to, but won't prefer it.

Three fingers swipe up is back and two fingers in a circle is save?! Not literally, but there's usually a dozen different gestures all with ambiguous meaning. At least ambiguous to me. But I don't have an immediate fix for the tablet interface.

I guess I'm an old fogy and prefer typing on a keyboard with my withered vestigial arms.