If you want to understand hamburgers on a fundamental level—any obscure factoid about their rise in fast-food culture, or which institutions forever changed the patty's DNA in America—all roads lead to George Motz. For years now, the author and filmmaker has traveled the country studying the art of making patties in road-side shacks and small town diners, absorbing the kind of intel that has transformed short-order cooks into national icons, and griddles into palimpsests of grease. 

But in preparation for his first cookbook, The Great American Burger Book: How to Make Authentic Regional Hamburgers at Home, there was one concern: Motz didn't want to go on a crusade divulging recipe secrets that have stood the test of time for nearly half a century. That's when the light bulb went off. Instead of breaking some sacred pact, Motz realized he "could pinpoint a method to a region. No one had ever done that before," he says. "Most people identified burgers by toppings." There were reasons for why methods became tied to certain places, and it became his job to crack the code.

For Motz, the burger is the perfect comfort food, the magic combination of sweet, salty, crunchy, soft, hot, and cold that helps to explain why its formula has been remixed endlessly. "A pulled-pork sandwich takes 16 hours to make. A cheeseburger takes two and a half minutes," he says. "It's inexpensive to make a good burger, and you don't have to do too much to end up with an enormously satisfying experience."

Even more so, many traditions developed out of necessity of the moment. "It's not like these things were thought about in a corporate lab somewhere and then presented at a tasting panel," he says. The deep-fried burger, Motz explains, came into existence when someone forgot to empty the grease and the patty floated to the top, signaling its readiness; smashing onions into a burger became a way to extend the beef for Oklahoma railroad workers who were on strike and short on cash. 

The recipes in Motz's book are a way to connect to the past, a view into burger life that might normally be confined to a 50-mile radius. "This is about celebrating regionality," he says. "Other than just making these at home, I encourage readers to visit these places. Sit there and talk to the workers in front of the open grill. It becomes a much better experience."

To understand the burger at its core, you must keep track of its regional variations,  from slugburgers in northern Mississippi, or Hot Pocket-like bierocks in the Nebraska/Kansas area. Here is an essential guide to regional burgers in America.