Background: Lithium is a light, metallic element and minerals containing it are most abundant in the Andes. John Cade introduced lithium carbonate for the treatment of mania in 1949, opening the era of modern clinical psychopharmacology. Lithium remains the most extensively studied mood-stabilizing agent. It has had a revolutionary impact in supporting bipolar manic-depressive disorder as a discrete diagnosis, and on psychiatric therapeutics. Methods: We survey the development of lithium treatment in psychiatry, including findings concerning effects on suicide. Results: Lithium is the most extensively studied treatment for bipolar disorder and the prototypical mood-stabilizing agent, despite emergence of anticonvulsants and modern antipsychotics. In addition to limiting recurrences of mania, and some reduction of recurrences of bipolar depression, lithium has demonstrated protective effe...