Communication between cells during early embryogenesis establishes the basic organization of the vertebrate body plan. Recent work suggests that a signalling pathway centering on Nodal, a transforming growth factor beta-related signal, is responsible for many of the events that configure the vertebrate embryo. The activity of Nodal signals is regulated extracellularly by EGF-CFC cofactors and antagonists of the Lefty and Cerberus families of proteins, allowing precise control of mesoderm and endoderm formation, the positioning of the anterior-posterior axis, neural patterning and left-right axis specification.