The definition of immunology as the science of the immune system that emerged in the 1960s provides a sound basis for both reconstructing its past and constructing its future. The choice of this point in time of course involves important consequences, on the one hand, sociological and institutional, epistemological and conceptual on the other. I will attempt to demonstrate that this perspective allows us to assess the history of immunology in an innovative way while elucidating in the process some of its theoretical paradoxes.