Penicillin is the drug of the twentieth century. It was the first of the antibiotics that, for decades after the Second World War, underpinned a popular belief that infectious disease had at last met its match. With the emergence of 'superbugs' in recent decades these hopes have faded. Acrossthe world, we are warned that widespread antibiotic abuse will inexorably erode the drugs' efficacy and our own earlier confidence in them. Penicillin pulls these...