Born in New York City the same year as Cajal, William Stewart Halsted didn't decide to study medicine until he was a senior at Yale. It was a choice that profoundly affected the surgical field, as Gerald Imber describes in his masterful biography, Genius on the Edge. Imber realistically portrays the agony of operations a century ago when the mortality rate was as high as 99 percent. Today it's 1 percent, in part because of Halsted, whose genius often came from common sense like

—Alfredo Quinones-Hinojosa