We're huge fans of everything Mike & Al, and we still constantly find ourselves recommending to folks their classic Backcountry Ski Book. If you're unfamiliar with Mike and Al's books, you're really missing out: both the writing and the illustrations are clear, concise and unpretentious, making for truly enjoyable reading and learning.
Not just for skiiers, about half the book contains great information on general backcountry safety, camping, and ethics that will be useful to anyone going out to them thar hills. The skiing specific chapters include plenty o' tips on equipment and technique. The authors give equal treatment to AT and tele gear, avoiding completely the totally useless arguments about which is better.
I didn't compare this edition to the last one, so I can't tell you what's new. I just picked it up and reread the whole thing. If you're like me and you can't remember what you had for breakfast, it's ten bucks well spent. Buy it on Amazon together with Backcountry Skiing and you are fully informed.