This issue of Hematology/Oncology Clinics, guest edited by Dr. Jennifer R. Brown, will focus on Chronic Lymphocytic Leukemia. This issue is one of six selected each year by our series consulting editors, Dr. George P. Canellos and Dr. Edward J. Benz. Topics discussed in this issue will include: Chronic Lymphocytic Leukemia: Do We Know the Cell of Origin Yet?; Significance of BCR Stereotypy; Prognostic and Predictive Implications of Cytogenetics and Genomics; Role of Epigenetics in Chronic Lymphocytic Leukemia; Genomics of Resistance to Targeted Therapies; First Line Therapy for Chronic Lymphocytic Leukemia; The Ongoing Unmet Needs in Chronic Lymphocytic Leukemia Therapy; BTK Inhibitors; Minimal Residual Disease; Should Undetectable MRD Be the Goal of Chronic Lymphocytic Leukemia Therapy?; Management of Chronic Lymphocytic Leukemia after Progression on BTK Inhibitors; Role of PI3K Inhibitors in Chronic Lymphocytic Leukemia; Can We Restore the Immunodeficiency of Chronic Lymphocytic Leukemia?; and Immune Therapy for Chronic Lymphocytic Leukemia