ABSTRACT
The identification of chronic lymphocytic leukemia (CLL) came about several decades after leukemia as a separate clinical entity was first described. Therefore, a historical sur vey of CLL must start with the review of those early years of hematology that followed the discovery and applications of microscopy and the development of methods of staining blood cells to distinguish the lymphoid from the myeloid hematopoiesis. Understandably, the numerous subtypes of all leukemias we recognize today share a common historical period when clinicians and pathologists battled with the question of whether leukemia was indeed a recognizable disease.
