The past few years have seen an explosion of information about genes that control the development of the neural crest, a structure unique to vertebrate embryogenesis. Many of these genes are mutated in human diseases that affect crest-derived lineages. At the same time, decades of work on the neural crest at the cellular level are generating new insights into the segregation of different lineages and the role played by environmental signals in the lineage-commitment process. The challenge now is to integrate the cellular and molecular genetic perspectives on neural crest development. This review attempts such a synthesis.