The second edition of Why we argue (and how we should) by Robert Talisse and our own Scott Aikin is now out. You can get it here or (what’s better) at your local bookstore.
Devoted readers of this site will recognize some of the ideas, but (and perhaps I’m biased) all will appreciate its lively approach to the topic of disagreement and informal logic. It’s primary virtue is that it’s a self-aware discussion of informal reasoning–it recognizes that everyone is already familiar with the metalanguage of argument and this is what amounts to its biggest challenges. Along these lines, the new edition has stuff on deep disagreement, the Owl of Minerva Problem, and online arguing.
It will be worth your time.