Cell-Cell Signaling in Development, Volume 150 covers new approaches and topics surrounding the diversity of animals, with recognized species now in the millions. Remarkably, the many distinct morphologies in the metazoan biosphere are generated by only a small number of genetically-encoded signaling systems that organize cells into patterned tissues, principally, the Wnt, Hedgehog, Bone morphogenic protein, fibroblast growth factor, Notch/Delta, and planar polarity systems whose roles orchestrating morphogenesis are widespread and evolutionarily conserved. Users will find the latest information on these elegant systems, along with conceptual links to signaling in plants and ideas that are emerging from recent progress.