Molecular diagnostics are essential in today's management of patients with hematological malignancies. In the current WHO classification of tumors, diseases are defined by morphologic, immunologic and genetic features reflecting the role of molecular diagnostics. This book summarizes the current approaches and impact of molecular diagnostics in the most common hematological malignancies (multiple myeloma, lymphoma, chronic lymphocytic leukemia, acute lymphoblastic leukemia, acute myeloid leukemia, myeloproliferative disorders, chronic myeloid leukemia, and myelodysplastic syndromes). Furthermore, molecular diagnostics do not only provide the basis for disease classification, prognostic assessment and treatment decisions, but also greatly contribute to continuous improvements in our understanding of underlying pathogenic events. Therefore, this book not only summarizes today's standard approaches of molecular diagnostics but also illustrates novel experimental strategies and techniques currently used in research laboratories. This comprehensive state-of-the-art overview was made possible by the invaluable contributions of a distinguished group of international investigators with outstanding expertise and track record in their field.