The Beautiful Structures of BAFF, APRIL, and Their Receptors -- BAFF Receptor Regulation of Peripheral B-Lymphocyte Survival and Development -- Regulation of B-Cell Self-Tolerance By BAFF and the Molecular Basis of Its Action -- Role of BAFF and APRIL in Antibody Production and Diversification -- Signal Transduction by Receptors for BAFF and APRIL -- TACI Signaling and Its Role in Immunity -- The BAFF/APRIL System in Autoimmunity -- Systemic Immune-Based Rheumatic Diseases: Blissless States of BLySfulness -- The Role of BAFF and APRIL in Regulating Human B-Cell Behaviour: Implications for Disease Pathogenesis -- Translation of BAFF Inhibition from Mouse to Non-human Primate and Human -- BLyS/BR3 Receptor Signaling in the Biology and Pathophysiology of Aggressive B-Cell Lymphomas -- Tipping the Scales of Survival: The Role of BLyS in B-Cell Malignancies. The BLyS/BAFF family of cytokines and receptors has captured and held the attention of B cell biologists during the last decade. Discovery of the two ligands and three receptors comprising this family has yielded a watershed of insights; fostering fresh paradigms in our views about the differentiation, selection, and homeostatic control of virtually all B cell subsets. Moreover, because these processes are intimately tied to the mechanistic underpinnings of immune tolerance and activation, increased understanding of these activities promises translational progress in autoimmunity, neoplasia, and transplantation.