Corn tortillas might be the simplest bread on earth: nixtamalized corn flour (masa harina), water, salt, and nothing else. No yeast, no oil, no kneading. The key ingredient is masa harina — corn that's been treated with an alkaline solution (traditionally cal, calcium hydroxide), dried, and ground. The nixtamalization process is what makes the corn nutritious and what gives real corn tortillas their characteristic flavor; regular cornmeal won't work. Maseca is the most widely available brand; Bob's Red Mill and Masienda make excellent specialty masa.