All biology only makes sense when seen in the light of evolution, and this is especially true for the nervous system. To understand any nervous system, we need to know how they vary and how this variation emerged in evolution. This volume brings together 43 fundamental chapters about nervous system evolution in an affordable single volume reference selected by the editor from two major reference works published by Academic Press Evolution of Nervous Systems, a comprehensive reference and The Encyclopedia of Neuroscience. The authors outline the changes in brain and nervous system organization that occurred from first vertebrates to present day fishes, reptiles, birds, mammals, and especially primates, including humans. The basic principles of brain evolution are discussed, as well as mechanisms of change, which involved gene expression and altered the courses of embryonic development.