John Piper speaking at Passion ’97. (Taken on my not-so-high-quality camera with real film that had to be sent away in a cute little black tube to be developed.) Dear Mr. Piper, It is 1997. Me and my 6 friends, ready to hit the road. I am 21 years old, and I just hopped into a van with six of my friends to drive 17 hours from Ames, Iowa to Austin, Texas for the Passion ’97 Conference. I have no idea who you are. Just a name and a photo. A middle-aged…