This summer I am taking a geology class at Stanford, and last week we were talking about the Sierra Nevada’s exfoliated granite domes. On the hour-long drive home, the class discussion got me thinking about my first extended backpack years ago in the Mineral King backcountry with my brother Jim. We were woefully unprepared: although it was late in the season, our only shelter was a flimsy plastic tube tent, and our food consisted of packets of tasteless, freeze-dried glop.