I know what you mean, SLHope, but it's not the appearance of the screen that's the issue for me. There's been quite a bit of research into all the extra peripheral reading one does as well as taking in the sentence you're concentrating on, and my mind has had mumble-mumblety years of training to do what it does based on the format of a book. Flicking backwards and forwards on a normal PC screen is plain awkward. Since a Kindle is designed so that 1 screen = 1 book page, it's easier, and the controls are certainly well thought out, but for a veteran bookworm it still requires a bit of retraining your body. No doubt if I'd started reading on a Kindle, I'd have similar complaints about paper-based novels.

As far as energy expenditure is concerned, you're probably right. However, I've hundreds of novels, mostly secondhand, that are decades old and that I've read dozens of times. Producing and distributing one of those books was almost certainly costlier in energy than an e-book, but has consumed literally none since then. My kids' books give an even more stark contrast, since they get exponentially more outings. How many Kindle recharges would it take for "The Badger's Bath" to be read at bedtime once a week for four years on the trot? Rhetorical question (because I don't know the answer), and I'm not saying you're wrong, but there's no getting away from the fact that a paper book is a one-off expenditure whilst the Kindle is an ongoing one, and there's got to be a cross-over point somewhere.