Sir Geoffrey Langdon Keynes was a British surgeon and author. He began his career as a physician in World War I, before becoming a doctor at St Bartholomew's Hospital in London, where he made notable innovations in the fields of blood transfusion and breast cancer surgery. Keynes was also a publishing scholar and bibliographer of English literature and English medical history, focusing primarily on William Blake and William Harvey.

William Harvey was an English physician who made influential contributions in anatomy and physiology. He was the first known physician to describe completely, and in detail, the systemic circulation and properties of blood being pumped to the brain and the rest of the body by the heart, though earlier writers, such as Realdo Colombo, Michael Servetus, and Jacques Dubois, had provided precursors of the theory.