In this issue of Hematology/Oncology Clinics, guest editors Drs. Jorge J. Castillo, Prashant Kapoor, and Shayna Sarosiek bring their considerable expertise to the topic of Waldenström Macroglobulinemia. Top experts in the field provide a focused update on the biology, diagnosis and management, and novel therapies for patients with Waldenström macroglobulinemia, a rare blood cell cancer characterized by an excess of abnormal white blood cells in the bone marrow.