Sir Peter Ratcliffe is a renowned British physician and researcher known for his groundbreaking work in the field of cellular responses to low oxygen levels, a process known as hypoxia. His research has significantly advanced the understanding of how cells adapt to reduced oxygen, which has implications for various medical conditions, including cancer and heart disease. In recognition of his contributions, Ratcliffe was awarded the Nobel Prize in Physiology or Medicine in 2019, sharing the honor with William Kaelin and Gregg Semenza. He has held prominent positions at institutions such as University of Oxford, where he continues to influence the field of medical research.