I'll agree with aaronbrethorst here: your books are going to out-dated regardless; it's the major downside to software hardcopy these days, especially web-focus

I'll agree with aaronbrethorst here: your books are going to out-dated regardless; it's the major downside to software hardcopy these days, especially web-focussed stuff. Saying that, Rails 3.0 to 3.1 isn't like 2.x to 3.0 (where your books WOULD have been useless). A lot of the changes are evolutionary, and there's nothing stopping you from learning on the latest 3.0.x branch with your book before tackling the (fairly straightforward) 3.0 to 3.1 upgrade process, once you've got your Rails knowledge bedded down.