The purpose of this text is to present a complete hematology course for Clinical Laboratory Science (CLS) students, as well as to provide a resource for clinical laboratory practitioners, medical students, and residents. It presents an in-depth study of cell counting, morphologic differentiation and evaluation, and related areas, such as flow cytometry, immunohistochemistry, and cytogenetics. A chapter on specific age groups covers the unique aspects of hematology in the pediatric and geriatric populations. A section on the etiology and treatment of leukocyte neoplasms has been included to provide some insight into the special considerations of oncologic disorders. Chapters begin with an outline and learning objectives, and color figures are presented as close to the citation as possible to facilitate understanding of the discussion. Most chapters end with a summary, and in many cases, review questions or case studies are included to assess or reinforce understanding of the material.