I found that retyping from a programming book helped me truly incorporate what I was learning more than simply reading it, in the same way that copying a painting is a deeper study than just scrutinizing one. When you're forced to physically go slow it gives your brain extra cycles to really chew on what it's doing. The translation from physical paper to computer was somehow more helpful too. Whenever I cheated and used the enclosed CD that chapter wasn't as solid in my mind.

Flipping back through a book has never been fully replicated electronically either, I think because you can't associate some info's location with its physical thickness in your fingers. We aren't just visual creatures, our brains constantly weave associations with all kinds of sensory input, and physical objects offer more.

I don't miss the price of those books though. I could never afford all the books I was interested in, and in those days you were lucky if your library had anything computer related at all.