A tablespoon of it will kill you, but most of us feel like death without it: we're talking about caffeine this episode. Inspired by a listener question — does green tea have more or less caffeine than black? and what about yerba mate? — Cynthia and Nicky explore the history and science of the world's most popular drug. Listen in as we discover the curious effect of birth control pills on how our bodies process it, calculate how much of an edge it gives athletes, and learn what dolphin dissection and the American Constitution have to do with each other, and with caffeine.