The statistics on books and eBooks make for interesting reading. Broadly speaking, what's happened is that teenagers' ownership of tablets and e-readers has increased significantly. And, as a consequence, a good half of their reading is now done on screens. What's more, when asked if an on-screen format motivates them to read more, the vast majority of teenagers agree, or at any rate, a majority of those who aren't regular or avid readers already. So, it seems that on the whole eBooks are having a positive effect on the reading habits of younger people. But a word of caution: because when it comes to retention of what's read, more than one study has found that children retain less of the information they read on screen than on paper. So, while they may help to encourage reading in general, it's not at all obvious that for study purposes, eBooks and tablets should be replacing the printed book.