Do books count as hardware or software? With old-fashioned physical books it's hard to tell. I always have a dozen checked out from the library, sitting by my bed. Of course I'm constantly scouring the web for information. But paper books are good when you're trying to learn a new subject, because you can develop a physical memory for where things are in the book, and pop it open to the right section whenever you feel like taking another crack at understanding something. Right now my favorites are these: