Ernest Hanbury Hankin was an English bacteriologist, aeronautical theorist and naturalist. Working mainly in India, he studied malaria, cholera and other diseases. He is often considered as among the first to detect bacteriophage activity and suggested that their presence in the waters of the Ganges and Yamuna rivers may have had a role in restricting the outbreaks of cholera. Apart from his professional studies, he took considerable interest in the Islamic geometric patterns in Mughal architecture as well as the soaring flight of birds, culture and its impact on education. He was sometimes criticized for being overzealous in his research methods.

A bacteriophage, also known informally as a phage, is a virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν, meaning "to devour". Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes and as many as hundreds of genes. Phages replicate within the bacterium following the injection of their genome into its cytoplasm.