> And what's so special about books in particular, anyway?

Concentration is a skill that needs to be practiced. A book is the easiest way to practice that skill.

Concentration is a skill that is useful broadly in human endeavors. I'll leave it to the social scientists to document the general damage that a lack of concentration does.

I can tell how much damage gets done depending upon the length since I last read a book. If I go a couple of months between books because of interruptions, my reading speed drastically slows down and my patience is really compromised. I didn't notice this happen before the rise of cell phones. Back then, a couple months of interruptions didn't seem to slow my reading speed much at all.