The DNA double helix, penicillin, the X-ray, insulin--these are routinely cited as some of the most important medical discoveries of the twentieth century. And yet, the 1949 discovery of lithium as a cure for bipolar disorder is perhaps one of the most important--yet largely unsung--breakthroughs of the modern era. In Lithium, Walter Brown, a practicing psychiatrist and professor at Brown, reveals two unlikely success stories: that of John Cade, the...