Receptor editing is a mode of immunological tolerance of B lymphocytes that involves antigen-induced B-cell receptor signaling and consequent secondary immunoglobulin light chain gene recombination. This ongoing rearrangement often changes B-cell specificity for antigen, rendering the cell non-autoreactive and sparing it from deletion. We currently believe that tolerance-induced editing is limited to early stages in B-cell development and that it is a major mechanism of tolerance, with a low-affinity threshold and the potential to take place in virtually every developing B cell. The present review highlights the contributions from our laboratory over several years to elucidate these features.