In some critical instances, our successes and our abilities to avoid the worst outcomes have been due to being prescient, vigilant, and determined to find effective fixes. Notable examples range from eliminating polio (by developing effective vaccines) to lowering the risks of commercial flying (by building more reliable airplanes and introducing better flight control measures), from reducing food pathogens (by a combination of proper food processing, refrigeration, and personal hygiene) to making childhood leukemia a largely survivable illness (by chemotherapy and stem cell transplants).
