Merguez in Morocco. Cotechino in Italy. Sai ua in Thailand. Every culture in the world, it seems, has a thing for sausage. It’s no wonder: Add a mix of spices to ground pork, beef, lamb, or venison (or a mix of any or all of them) and you have a self-contained dish as rich as most meals. And that’s just the starting point. Here’s our guide to the wide world of sausages.