Heinrich Hermann Robert Koch (11 December 1843 – 27 May 1910) was a Prussian physician. He became famous for isolating Bacillus anthracis (1877), the Tuberculosis bacillus (1882) and the Vibrio cholerae (1883) and for his development of Koch's postulates.

He was awarded the Nobel Prize in Physiology or Medicine for his tuberculosis findings in 1905. He is considered one of the founders of microbiology, inspiring such major figures as Paul Ehrlich and Gerhard Domagk.

Heinrich Hermann Robert Koch was born in Clausthal, Prussia, one of the German states as the son of a mining official. He studied medicine under Friedrich Gustav Jakob Henle at the University of Göttingen and graduated in 1866. He then served in the Franco - Prussian War and later became district medical officer, Wollstein (Wolsztyn), Prussian Poland. Working with very limited resources, he became one of the founders of bacteriology, the other major figure being Louis Pasteur.

After Casimir Davaine showed the direct transmission of the anthrax bacillus between cows, Koch studied anthrax more closely. He invented methods to purify the bacillus from blood samples and grow pure cultures. He found that, while it could not survive outside a host for long, anthrax built persisting endospores that could last a long time. These endospores, embedded in soil, were the cause of unexplained "spontaneous" outbreaks of anthrax. Koch published his findings in 1876, and was rewarded with a job at the Imperial Health Office in Berlin in 1880. In 1881, he urged the sterilization of surgical instruments using heat.

In Berlin, he improved the methods he used in Wollstein, including staining and purification techniques, and bacterial growth media, including agar plates (thanks to the advice of Angelina and Walther Hesse) and the Petri dish, named after its inventor, his assistant Julius Richard Petri. These devices are still used today. With these techniques, he was able to discover the bacterium causing tuberculosis (Mycobacterium tuberculosis) in 1882 (he announced the discovery on 24 March). Tuberculosis was the cause of one in seven deaths in the mid 19th century.

In 1883, Koch worked with a French research team in Alexandria, Egypt, studying cholera. Koch identified the vibrio bacterium that caused cholera, though he never managed to prove it in experiments. The bacterium had been previously isolated by Italian anatomist Filippo Pacini in 1854, but his work had been ignored due to the predominance of the miasma theory of disease. Koch was unaware of Pacini's work and made an independent discovery, and his greater preeminence allowed the discovery to be widely spread for the benefit of others. In 1965, however, the bacterium was formally renamed Vibrio cholera Pacini 1854.

In 1885, he became professor of hygiene at the University of Berlin, then in 1891 he was made Honorary Professor of the medical faculty and Director of the new Prussian Institute for Infectious Diseases (eventually renamed as the Robert Koch Institute), a position from which he resigned in 1904. He started traveling around the world, studying diseases in South Africa, India, and Java. He visited what is now called the Indian Veterinary Research Institute (IVRI), Mukteshwar, on request of the then Government of India to investigate on cattle plague. The microscope used by him during that period was kept in the museum maintained by IVRI.

Probably as important as his work on tuberculosis, for which he was awarded a Nobel Prize (1905), are Koch's postulates, which say that to establish that an organism is the cause of a disease, it must be:

• found in all cases of the disease examined;
• prepared and maintained in a pure culture;
• capable of producing the original infection, even after several generations in culture;
• retrievable from an inoculated animal and cultured again.

Koch's pupils found the organisms responsible for diphtheria, typhoid, pneumonia, gonorrhoea, cerebrospinal meningitis, leprosy, bubonic plague, tetanus, and syphilis, among others, by using his methods.

Robert Koch died on 27 May 1910 from a heart attack in Baden-Baden, aged 66.

The crater Koch on the Moon is named after him. The Robert Koch Prize and Medal were created to honour Microbiologists who make groundbreaking discoveries or who contribute to global health in a unique way. The now defunct Robert Koch Hospital at Koch, Missouri (south of St. Louis, Missouri), was also named in his honor. A hagiographic account of Koch's career can be found in the 1939 Nazi propaganda film Robert Koch, der Bekämpfer des Todes (The fighter against death), directed by Hans Steinhoff and starring Emil Jannings as Koch.

Because the construction efforts were jeopardized by malaria outbreaks on Veliki Brijun Island which occurred during summer months, at the turn of the century, the Austrian steel industrialist Paul Kupelweiser had invited the famous physician Robert Koch, who at the time studied different forms of malaria and quinine based treatments. Koch accepted the invitation and spent two years, from 1900 to 1902, on the Brijuni Islands Archipelago. According to Koch’s instructions, all the ponds and swamps where malaria - carrying mosquitoes hatched were reclaimed and patients were treated with quinine. Malaria was thus eradicated by 1902 and Kupelwieser erected a monument to Koch, which still stands in vicinity of the 15th century Church of St. German on Veliki Brijun Island.