André Michel Lwoff was a French microbiologist, geneticist and protozoologist, who received the ‘Nobel Prize in Physiology or Medicine’ in 1965 along with two French biologists François Jacob and Jacques Monod for his contributions in the discoveries regarding genetic control of enzyme and synthesis of virus. Together with Jacob and Monod he contributed in comprehending the lysogeny or the lysogenic cycle mechanism where bacteriophage, a bacterial virus, causes infection to bacteria which is then transferred to succeeding generations of bacteria entirely by way of cell division of its host. He showed that the infection is passed on in a non-infective form, which is called a prophage. He also showed that the prophage under some conditions engender an infective form that results in lysis or breaking down of the membrane of the bacterial cell and the viruses thus released due to such disintegration can infect other hosts of bacteria. He had done significant research on poliovirus, microbiota and bacteriophages at the renowned ‘Pasteur Institute’ of France where he served as departmental head. He received several honours and awards including the ‘Leeuwenhoek Medal’ from the ‘Royal Netherlands Academy of Arts and Sciences’ in 1960 and the ‘Grand Prix Charles-Leopold Mayer’ from the French ‘Académie des Sciences’ in 1964. His written works include ‘Problems of Morphogenesis in Ciliates’ (1950) and ‘Biological Order’ (1962).