Andrew Smith, the culinary historian who authored the indispensable Oxford Companion to American Food and Drink (Oxford University Press, 2007), has made it his mission to document the way Americans eat. In October, Columbia University Press published Smith's latest book, Eating History: 30 Turning Points in the Making of American Cuisine. Smith says that, after spending so many years examining the provenance of individual American foods, from ketchup to hamburgers to peanut butter, he wanted to pull back and look at the arc of American culinary history from a broader perspective. "I started seeing cross-connections between items," he says. "I started asking, How did we change? When did we change?" Smith ultimately pinpointed 30 watershed events, innovations, and inventions that hailed a new way of producing, cooking, selling, or eating food in the United States. We've collected Smith's fascinating findings, in a very abridged form and in no particular order.