© 2016 Elsevier Inc. All rights reserved. The development of the central nervous system (CNS) is an astonishing phenomenon. A simple sheet of the earliest precursor cells in the embryo transforms into the regional complexities of the brain and spinal cord. There is remarkable conservation of the processes involved in all animals, but there is increasing complexity with evolutionary advancement. Within this developing CNS, characteristic subtypes of nerve cells emerge with unique morphologies, functions, and connectivity. Each nerve cell must “wire up” in highly specific ways to produce the functional circuits that underlie brain function. Our early view of this process being programmed to a high degree of precision in early embryonic development has been changed by evidence for a far less rigorous process, where errors are made, nerve cells are eliminated, and neural function sculpts the formation of connections. Another tenet that has been reviewed is the assumption that once the brain had formed it was stable and “hardwired” with limited or no ability to change and only a negative response to damage and disease. We now know of intrinsic repair mechanisms and plastic changes to connectivity that occur even in the adult brain. There is a clear fascination in understanding how the complexity of the brain is established and how nerve cells generate circuits that underpin all our perceptions, thoughts, and actions. This knowledge of neural development also has profound implications for our understanding of disorders and diseases that affect normal brain function. Ultimately understanding how specific nerve cells are formed, connect, and survive has the potential to allow the therapeutic restoration of function.