Peter Charles Doherty is an Australian immunologist who shared the 1996 Nobel Prize in Physiology or Medicine with Rolf Zinkernagel for the discovery of how the immune system recognizes virus-infected cells. Working at the John Curtin School of Medical Research in Canberra in the early 1970s, Doherty and Zinkernagel demonstrated that cytotoxic T lymphocytes recognize infected cells only when viral peptides are presented in the context of self major histocompatibility complex (MHC) molecules — a principle now called MHC restriction. This insight revealed the molecular basis of cellular immunity: T cells see fragments of viral proteins bound to host MHC molecules, not free antigens. This understanding is foundational to vaccine design, organ transplantation immunology, tumor immunology, and the development of T cell-based cancer therapies. Doherty is also widely known as a public health communicator, particularly on influenza pandemic preparedness.