Final answer:
Florence Nightingale was a key historical figure in nursing who wrote about her epidemiological findings from the Crimean War, leading to improved military medical care.
Step-by-step explanation:
Florence Nightingale was a pioneering figure in nursing who became famous for her work during the Crimean War. In 1854, she led a group of nurses to care for British soldiers, keeping meticulous records that formed the basis of the field epidemiology. Nightingale wrote about her findings in a book published in 1858, in which she used a wedge chart histogram to expertly depict that the majority of deaths were due to preventable infectious diseases, not combat wounds, mainly caused by poor sanitation conditions. Her work led to considerable reforms in medical care within the British military.