Following an immune response two types of differentiated B cells persist in the memory pool: plasma cells, which confer immediate protection by the secretion of specific antibodies; and memory B cells, which confer rapid and enhanced response to secondary challenge. We will review recent advances in understanding the heterogeneity, dynamics, and persistence of human memory B cells and plasma cells as well as new methods to isolate human monoclonal antibodies. These findings offer new insights into the human B cell response, which are relevant for vaccination and therapeutic intervention.