The understanding of B cell biology has increased and expanded enormously in the last three decades. It is now known that B cells, in addition to just differentiating into antibody-secreting cells, serve many other vital functions. For example, their roles as antigen-presenting cells and cytokine-producing cells as well as effector cells and regulatory cells are well appreciated now. Indeed, the pathologic role of B cells in many autoimmune disorders may be largely autoantibody-independent. Today, the B cell is of considerable interest not only to immunologists but also to mainstream clinicians and scientists. The current volume covers the latest information on the functions of B cells in normal and disease states, and their therapeutic antagonism. Chapters cover cutting-edge topics from the basic to the clinical, including B cells in infection and autoimmunity, CD19-CD21 signal transduction complex, marginal zone B cell physiology and disease, B cell growth and differentiation, their role in rheumatoid arthritis, SLE treatment, the BAFF/APRIL system and B lymphocyte malignancies. This book is recommended reading for cellular and molecular immunologists as well as for rheumatologists, hematologists and clinical immunologists, and all those interested in human diseases in which B cells play an important contributory role.