Heinrich Hermann Robert Koch was a researcher from Germany who studied the causative agents of infectious diseases in various parts of Europe, Africa, and Asia during the late nineteenth and early twentieth centuries. Koch developed what researchers call Koch’s postulates, which are four criteria designed to establish whether a bacterium causes a certain disease, and as of 2025, many researchers still use Koch’s postulates to guide their research. He also received the Nobel Prize in Physiology or Medicine for his discovery of Mycobacterium tuberculosis, which is the bacterium responsible for tuberculosis, an infectious disease that primarily attacks the lungs. Koch’s research on identifying disease-causing bacteria for various infectious diseases has advanced disease prevention and treatment, especially for tuberculosis, which has the ability to transmit from mother to child.