 On October 31st, 180 million or so Americans will celebrate Halloween by trick-or-treating, handing out candy, carving pumpkins, and, of course, dressing up. Americans spent more than $9 billion on Halloween last year, much of it on costumes, which have come a long way in recent years. Not long ago, commercial costumes consisted of front-only masks and thin plastic smocks. They were shabby and a little, well, cynical. Today, Halloween revelers have vastly better options. Why? An economic idea helps us understand. Specialization. It's the idea that people and businesses focus on a particular skill or stage of production, increasing efficiency and output. We take advantage of specialization in the division of labor every day through the food we eat, the houses we live in, and, on Halloween, the costumes we wear. Today, specialization is global. People and companies worldwide trade on their strengths. It helps explain why a DC Comics fan can order a screen-accurate Batman suit, boots, and a mask for the price of a tank of gasoline. So, as you hand out candy to children and enchanting costumes this Halloween, remember that without global trade, Luke Skywalker would still look like this.