Physiology or medicine is the third prize category Alfred Nobel mentioned in his will. Nobel had an active interest in medical research. He came into contact with Swedish physiologist Jöns Johansson through Karolinska Institutet around 1890. Johansson worked for a brief period in Nobel's laboratory in Sevran, France during the same year. The Nobel Prize in Physiology or Medicine is awarded by the Nobel Assembly at Karolinska Institutet. This volume is a collection of the Nobel lectures delivered by the Nobel laureates, together with their biographies and the presentation speeches for the period 2016–2020. List of Nobel laureates and their award citations:(2016) Yoshinori Ohsumi "for his discoveries of mechanisms for autophagy";(2017) Jeffrey C Hall, Michael Rosbash and Michael W Young "for their discoveries of molecular mechanisms controlling the circadian rhythm";(2018) James P Allison and Tasuku Honjo "for their discovery of cancer therapy by inhibition of negative immune regulation";(2019) William G Kaelin Jr, Sir Peter J Ratcliffe and Gregg L Semenza "for their discoveries of how cells sense and adapt to oxygen availability";(2020) Harvey J Alter, Michael Houghton and Charles M Rice "for the discovery of Hepatitis C virus";