If you could choose to master a single ingredient, no choice would teach you more about cooking than the egg. It is an end in itself; it's a multipurpose ingredient; it's an all-purpose garnish; it's an invaluable tool. The egg teaches your hands finesse and delicacy. It helps your arms develop strength and stamina. It instructs in the way proteins behave in heat and in the powerful ways we can change food mechanically. It's a lever for getting other foods to behave in great ways. Learn to take the egg to its many differing ends, and you've enlarged your culinary repertoire by a factor of ten.