To determine the most beneficial developments in the medical field through out history, one would have to consider multiple factors because an indeterminable number of people have been helped in some way from every advancement. Recognition for all the discoveries and vaccines, as well as the men and women who represented them is due. Therefore any list of medical achievements is fated to leave some things out; in a field as vast as medicine, one revelation causes another which causes another, creating limitlessness. Logically, man began by understanding his physical self in the most basic ways. Moving from outside to in, surgery and disection are some of the earliest known medical practices. Medical treatment and medicine itself, however, out dates known historical data. Next came the schools of medicine and continued the expansion of the field as a whole through publication. Creating and constantly improving hospitals has always been a must for thriving societies. Another important attribution to medicine would be illness; things like plaueges and epidemics were critical for expanding our curing powers. Advancements in technowledgy like tools and machines allowed us to do things man was previously incapable of. Finally vaccinations would be the latest and greatest achievements in medicine. For so long treatment was  standard but curing and preventing have brought us all into a new era. Obviously it's not easy to reduce such a vast area of study into a mini-biography such as this, but it comes down to study, practice, information, and technowledgy, but most importantly: the people who do it.