Between 1935 and 1944 the field of microbiology, and by implication medicine as a whole, underwent dramatic advancement. The discovery of the extraordinary antibacterial properties of sulphonamides, penicillin, and streptomycin triggered a frantic hunt for more antimicrobial drugs that was to yield an abundant harvest in a very short space of time. By the early 1960s more than 50 antibacterial agents were available to the prescribing physician and, largely by a process of chemical modification of existing compounds, that number has more than tripled today. We have become so used to the ready...