These published proceedings of a Neurosciences Research Program Colloquium do not deal exhaustively with particular cortical issues--rather, they convey the highlights of the topic, beginning with a series of presentations on the ontogenetic and morphogenetic development of the cerebral cortex followed by a systematic view of the remarkable explosion during the last decade of our knowledge of the cellular organization and connectively of the cortex. All of the topics in the book are put into perspective in an opening keynote by W. Maxwell Cowan. He there observes that theoretical constructs (or the lack of them) are the weakest aspect of neurobiology at the moment. Thus the book's final section (with contributions by three Nobel laureates--Francis Crick, Gerald Edelman, and Leon Cooper--among others) is a meaningful new effort toward redressing the balance.