“Man is not going to wait passively for millions of years before evolution offers him a better brain.” These words are attributed to the 20th century Romanian psychopharmacologist Corneliu Giurgea, an early advocate of cognitive enhancement—that is, the use of medications or other brain treatments for improving normal healthy cognition. Contemporary attempts at cognitive enhancement involve an array of drugs and devices for modifying brain function, such as pills taken by students to help them study, or electrical stimulators focused on prefrontal cortex by electronic game players (“e-gamers”) to sharpen their skills. What is known about current methods of cognitive enhancement? What specifically do they enhance, for whom, and with what risks? We know surprisingly little.