The search for relief from pain and sickness is a story of discovery. Some discoveries were quite sudden, such as Alexander Fleming's observation of bacteria dying in the presence of a certain mold, which led to the discovery of penicillin. Other discoveries were incremental. Gregor Mendel observed the patterns of inheritance, which led--years later--to the discovery of genes and the structure of DNA--knowledge that can now be used to predict and prevent human genetic disorders. This compelling volume reviews the far-reaching impact of history's most important medical discoveries.