Perhaps it's just me, but I find it difficult and tiring to read off the screen. It's only when I print my documents off that I see all the typos and errors! I was a science teacher until quite recently and as far as I'm concerned, there's no danger of on-line text books taking over from real, hands on, dog eared text books. I have many years’ experience of using both media in my classes:
Scenario 1: waltz into class, hand out text books, turn to page 34 and get on with the lesson - max time taken, about 4 minutes.
Scenario 2: Waltz into class, find the laptop cabinet is locked, send pupil to prep room for key. Hand out laptops, 25 machines for 28 kids, hmm! Spend time persuading kids to share. Find that 6 machines have flat batteries, organise more sharing. Wait 10 minutes while the machines boot up and find the feeble signal from the school network. Four kids claim to have 'forgotten' their passwords - send to IT room to get them re-set. Discover that three machines have ‘just turned themselves off, sir, honest’. Find that some little tyke has altered the resolution on half the machines and we've got 4inch high text and four words on the screen. Finally get 28 kids around the 8 working machines and onto the website - except that half of them are on Facebook. Max time wasted? Well, in one case 45 minutes, before finally giving up.
Also, it’s not just that, from a technical point of view, books are infinitely more robust and reliable than computers. No, from the teacher's point of view, you can't 'cut and paste' screeds of irrelevant twaddle from a book; thus making marking a lot less tedious and the content more relevant (well … sometimes). And the big winner for the kids is… you can't draw exaggerated reproductive organs and vulgar speech bubbles in biro to a screen like you can to a book! Need I say more?