This is what I've been using to draft the coffee roasting book I've been working on. It's a hard cover Moleskine book that came in a swag bag from some event. Between the hard cover and the strap, I can fit it in my pocket without worrying about it getting destroyed and I can write notes as I think of them no matter where I am. The contents get moved to a computer, organized, and fleshed out when I have larger time blocks and I'm in the right state of mind for working on that.