In 1845, John Hughes Bennett, in Edinburgh, described the case of a 28-year-old slater who presented with massive enlargement of his liver, spleen, and lymph nodes. Two weeks following this description, Rudolph Virchow, in Berlin, probably unaware of Bennett’s presentation, described the case of a 50-year-old lady, a cook, with a huge spleen. It is generally agreed that these case reports must have been the first accurate descriptions of chronic myeloid leukemia (CML). Later in 1870, Ernst Neumann, in Koenigsberg (Germany), was credited for recognizing the central role of the bone marrow in leukemias. In 1879, a German surgeon, Gustav Heuck, described two young patients with massive splenomegaly and abnormal leucocytes and nucleated red cells in the blood-a condition we would accept as primary myelofibrosis. Paul Ehrlich, in 1891, and Otto Naegeli, in 1900, developed various laboratory dyes or “stains” that allowed the leukemias to be more clearly separated.