Book excerpt: This issue of Hematology/Oncology Clinics, Guest Edited by Dr. Jonathan W. Friedberg, is devoted to Follicular Lymphoma. This issue is one of six selected each year by our series Consulting Editors, George P. Canellos and Edward J. Benz. Articles in this important issue include: Epidemiology of Follicular Lymphoma, Pathogenesis of Follicular Lymphoma, Circulating tumor DNA and MRD assessment in Follicular Lymphoma, Clinical and biological prognostic factors in Follicular Lymphoma, Vitamin D and Follicular Lymphoma, Initial Treatment of Early Stage and Low Tumor Burden Follicular Lymphoma, Initial Treatment of High Tumor Burden Follicular Lymphoma, Maintenance Antibody Therapy of Follicular Lymphoma, Cellular Therapy in Follicular Lymphoma, Immunomodulatory Agents in Follicular Lymphoma, Phosphoinositide 3-Kinase Inhibition in Follicular Lymphoma, Novel Agents Beyond Immunomodulatory Imide Drugs and Phosphoinositide 3-Kinases for Follicular Lymphoma, Early progression of Follicular Lymphoma, Biological Basis of Histological Transformation, and Treatment of Histological Transformation.