Because of difficulties in isolation, it has taken some time to arrive at a reasonable outline of the dendritic cell system. With the international effort that is assembled here, the main features of this system are apparent. There are now several criteria that allow for dendritic cell identification, there is understanding of tissue distribution and the interconnections between different compartments, there is new data on the production and maturation components of this system, and there are many observations that help explain antigen presentation, T cell stimulatory function, and behaviour in situ. The contributions of our Dutch hosts should be stressed. Many have energized the study of lymphoid, mononuclear phagocyte, and dendritic cell systems. The beginnings were made by Koenig, Langevoort, Thorbecke and van Furth, continued with Veldman, Nieuwenhuis, Hoefsmit, Drexhage, van Ewijk, Dijkstra, Kraal, Kamperdijk, and now there are many investigators in the biology of antigen presentation, one understands why it is appropriate to be in Holland. Holland even geographically is a "dendritic cell" [Fig 4].