Cornbread Nation 2: The United States of BarbecueSouthern barbecue and barbecue traditions are the primary focus of Cornbread Nation 2, our second collection of the best of Southern food writing. Barbecue is the closest thing we have in the United States to Europe's wines or cheeses; drive a hundred miles and the barbecue changes, writes John Shelton Reed. Indeed, no other dish is served a dozen different ways just between Memphis and Birmingham. In tribute to what Vince Staten calls the slowest of