SOMMAIRE : I. Histology of Non Neoplastic Hematopoietic Tissues A. Lymph Nodes 1. Normal Form and Function 2. Developmental and Degenerative Diseases 3. Hyperplastic and Dysplastic Changes B. Spleen 1. Normal Form and Function 2. Developmental and Degenerative Diseases 3. Hyperplastic and Dysplastic Changes C. Thymus 1. Normal Form and Function 2. Developmental and Degenerative Diseases 3. Hyperplastic and Dysplastic Changes D. Bone Marrow 1. Normal Form and Function 2. Developmental and Degenerative Diseases 3. Hyperplastic and Dysplastic Changes II. Histology of Hematopoietic Neoplasia, The development of Classification Systems for Hematologic Neoplasia from Virchow to WHO 2000. A. Lymph Nodes 1. B-Cell Neoplasms 2. T-Cell Neoplasms 3. Myeloid Leukemias B. Spleen 1. B-Cell Neoplasms 2. T-Cell Neoplasms 3. Myeloid Leukemias C. Thymus 1. B-Cell Neoplasms 2. T-Cell Neoplasms 3. Myeloid Leukemias D. Bone Marrow 1. Precursor B-Cell Neoplasms 2. Precursor T-Cell Neoplasms 3. Acute Myeloid Leukemias 4. Chronic Myeloid Leukemias E. The Hystiocytoses Index