Magnus Manske · CC BY-SA 3.0

Stanley Falkow spent over 50 years working out how bacteria actually cause disease, formulating the molecular version of Koch's postulates that has guided infectious-disease research since the 1980s. He was also among the first scientists to study antimicrobial resistance, describing how resistance spreads between organisms through horizontal gene transfer — a mechanism now central to understanding the growing threat of drug-resistant infections.