"NPR's Coffee Week is winding down, but we'd be remiss if we didn't give some space to caffeine, the most widely used stimulant drug in the world."

"As much as we may enjoy the nutty dark roast aromas and the sensations of a warm beverage, coffee is often just a caffeine delivery system for a groggy brain. Approximately 80 percent of caffeine is consumed in the form of coffee, and in the U.S., we average about two cups of coffee per day. That 200 milligrams of caffeine affects our brains, our performance, and maybe even our health."

"Many believe that humanity's caffeine addiction has wrought a lot of benefits. Earlier in the week, historian Mark Pendergrast told us about how coffee (and caffeine) helped Western civilization "sober up" enough to get down to business. And Jerry Seinfeld claimed coffee has made us a more productive society."