In a disused hospital pantry in the 1940s, an Australian doctor discovered an astonishing treatment for bi-polar disorder (or manic-depression, as it was then known). It would change the way we think about mental illness and mark the beginning of psychopharmacology – using drugs to manage psychiatric conditions. It would take 20 years of struggle before lithium treatment was finally accepted, but the scientists and psychiatrists who followed Cade’s lead persevered. Their work has meant a chance at stability for hundreds of thousands of people around the world, and lithium remains the benchmark for bi-polar treatment today.