This fascicle on non-neoplastic disorders is devoted to the assessment of bone marrow in pediatric and adult patients. Although the emphasis is clearly on the successful diagnosis of non-neoplastic bone marrow disorders, neoplastioc processes are briefly highlighted in discussions of differential diagnostic considerations. The early chapters focus on hematopoiesis, bone marrow topobiology, indications for bone marrow examination and the utility of specific types of bone marrow specimens in diagnostic assessment...In addition, blood findings are integrated with the bone marrow pathology in each chapter. Lineage-based non-neoplastic erythroid, myeloid, megakaryocytic and lymphoid disorders are discussed as well as bone marrow findings in patients with systemic nonhematologic disorders.