Art collecting has traditionally been the domain of wealthy individuals in search of rewards beyond the purely financial.

Behavioral economists have shown that a sizable percentage of people are willing to pay real money to punish people who are taking from a common pot but not contributing to it. Just to insure that shirkers get what they deserve, we are prepared to make ourselves poorer.

Intellectual-property rules are clearly necessary to spur innovation: if every invention could be stolen, or every new drug immediately copied, few people would invest in innovation. But too much protection can strangle competition and can limit what economists call 'incremental innovation' - innovations that build, in some way, on others.

The stock market has an insidious effect on C.E.O.s' moods, because of its impact not just on their companies but on their own bank accounts.

Speculators get a bad rap. In the popular imagination they're greedy, heedless, and amoral, adept at price manipulations and dirty tricks. In reality, they often play a key role in making markets run smoothly.

Medical tourism can be considered a kind of import: instead of the product coming to the consumer, as it does with cars or sneakers, the consumer is going to the product.

The value of a currency is, ultimately, what someone will give you for it - whether in food, fuel, assets, or labor. And that's always and everywhere a subjective decision.