This literature review provides data on the temporal sequence in which gyri, sulci, and fissures first become apparent on anatomic specimens of the developing brain surface. Ultrasonic display of these anatomic features lags behind the initial appearance of the features by a variable interval, greater in early gestation and diminishing in late gestation. MR imaging, especially three-dimensional surface rendering, displays the degree of surface maturation to advantage. Different publications have provided variable estimates of the time course of surface maturation, leading to discordance in the date tabulated. None-the-less, the overall sequence is clear and the surface features are useful in assessing the degree of fetal-neonatal maturity by ultrasonography and by MR imaging.