This article reviews key recent findings in the field of human cortical development. This development is divided into three major time-dependent phases: neural proliferation of inhibitory and excitatory neurons in spatially distinct regions, migration through multiple cellular boundaries, and maturation through morphologic changes that result in the elaboration of dendrites and axons and that establish the multitude of cellular contacts that underlie neuronal processing. Many of the neurocognitive disorders treated in the clinic can trace their origin to a disorder in one or more of these key steps. Along with this update, work is highlighted that offers a glimpse at the future of therapy for developmental brain disorders that can result from disorders of these cellular events.