The dendritic shape of a given cell is by no means indicative of its origin and function. This is exemplified best by the ontogenetic and functional heterogeneity of dendritic cells in the skin. Even when focusing on bone marrow-derived dendritic cells, the mammalian skin contains at least three distinct lineages of dendritic cells, including Ia+ nonlymphoid dendritic cells (epidermal and dermal Langerhans cells, veiled cells in the lymphatics), dendritic epidermal T cells (mouse), and less well-characterized dermal dendrocytes. Methods exist that allow us to isolate and to purify these cells, to study their phenotype and function, and, thus, to clarify their role in both physiologic and pathologic conditions of the skin.