This book discusses the research advances in leukemia with the help of advanced research-focused information. Leukemias are a class of heterogeneous neoplastic disorders varying essentially in terms of morphological, immunophenotypic, cytogenetic and molecular features of malignant cells. These features indicate a difference in the spectrum of basic biological alterations involved in malignant transformation, and/or variations in the level of hematopoietic stem cells hierarchy where the transforming events occur. For continuous and extensive inflow of latest information regarding the pathogenesis and treatment of leukemias, it is necessary to regularly update our knowledge of this topic. The primary objective of this book is to bring together the diagnosis and management of acute and chronic leukemias with comprehensive and concise information on important theoretical and practical issues of the biology, clinical presentation, diagnosis, treatment and follow up of patients with leukemias.