The evolution of research into inherited haemoglobin disorders posed some fascinating questions for historians of the medical sciences in the twentieth century. Of particular interest is how the study of what initially seemed to be a group of rare genetic anaemias turned out to be the forerunner of a new era of medical science. For, in effect, it was the description of their molecular basis that led to the idea of 'molecular disease', and, later, to 'molecular medicine' — a change of emphasis from the characterization of illness in patients and their organs to a description of its pathology at the level of cells and molecules.