Love may be a many splendored thing, but it is not the only factor considered when couples choose to marry. People wed, in part, to share gains from a division of labor. Household chores, for example, involve less drudgery if one spouse cooks and mows the lawn while the other pays the bills and buys the groceries. And getting the dishes washed takes less than half the time when one person rinses crockery while the other loads the dishwasher.

The division of labor entails dividing the work required to produce a given good or accomplish a particular task.

One autoworker may install windshields, another, gas tanks, a third, hubcaps, and so on. Assembly lines yield significantly more cars than if each worker produced entire cars alone. Gains from the division of labor arise because: (a) teamwork fosters productivity (no surgeon could do heart transplants alone), and (b) people develop expertise in particular jobs (practice improves quality and reduces error). What is a "key grip?" A "best boy?" Long lists of credits that scroll on-screen to end a film barely hint at the divisions of labor behind such complex products as blockbuster movies, skyscrapers, or jumbo jets.