Craniosynostosis occurs in approximately 1:2000 live births. It may affect the coronal, sagittal, metopic and lambdoid sutures in isolation or in combination. Although non-syndromic synostoses are more common, over 150 genetic syndromes have been identified. Recent advances in genetic mapping have linked chromosomal mutations with craniosynostotic syndromes. Despite the identification of these genetic mutations, the fundamental biomolecular mechanisms mediating cranial suture biology remain unknown. Today, many laboratories are investigating murine cranial suture biology as a model for human cranial suture development and fusion. Normal murine cranial suture biology is very complex, but evidence suggests that the dura mater provides the biomolecular blueprints (e.g. the soluble growth factors), which guide the fate of the pleuripotent osteogenic fronts. While our knowledge of these dura-derived signals has increased dramatically in the last decade, we have barely begun to understand the fundamental mechanisms that mediate cranial suture fusion or patency. Interestingly, recent advances in both premature human and programmed murine suture fusion have revealed unexpected results, and have generated more questions than answers.