I'm a little surprised at the number of people that are saying "paper" or "printer". I agree. The technology to read complex technical topics online just isn't there yet, remarkably. I do plenty of reading online as I'm working on stuff, and I read recreationally (fiction and non-fiction) almost entirely on a Kindle. But for some stuff, there's just no substitute yet for paper. High contrast, portable, annotatable, and persistent.
Yeah there's this weird attitude that's quite prevalent that there's something wrong with printing things out on paper. There isn't. Paper that we buy in the west to use for printing things out on is almost all sustainably farmed timber, and consuming it promotes the creation of sustainably farmed young growth wood, which absorbs CO2 very effectively.
