The processes by which diversity is acquired and maintained during embryogenesis have been repeatedly described but are as yet not understood. One fascinating example of diversity following gastrulation is epidermal organogenesis and in particular embryonic tooth morphogenesis. Tooth morphogenesis in situ and in vitro encompasses such interesting developmental problems as epithelial-mesenchymal interactions, cytodifferentiation, dentine and enamel extracellular matrix production, mineralization, issues of form and enamel maturation. In vitro methods provide access to many of these problem areas. This presentation will review selected issues related to amelogenesis in vitro and will emphasize avenues for future research.