Successful development in multicellular eukaryotes requires cell-cell communication and the coordinated spatial and temporal movements of cells. The complex array of networks required to bring eukaryotic development to fruition can be modeled by the development of the simpler prokaryote Myxococcus xanthus. As part of its life cycle, M. xanthus forms multicellular fruiting bodies containing differentiated cells. Analysis of the genes essential for M. xanthus development is possible because strains with mutations that block development can be maintained in the vegetative state. Development in M. xanthus is induced by starvation, and early events in development suggest that signaling stages have evolved to monitor the metabolic state of the developing cell. In the absence of these signals, which include amino acids, alpha-keto acids, and other intermediary metabolites, the ability of cells to differentiate into myxospores is impaired. Mutations that block genes controlling gliding motility disrupt the morphogenesis of fruiting bodies and sporogenesis in surprising ways. In this review, we present data that encourage future genetic and biochemical studies of the relationships between motility, cell-cell signaling, and development in M. xanthus.