Here we are on the brink of the twenty-first century. While the history of neurological and psychological research goes back at least two hundred years, the heavy work commenced in the twentieth century. In a hundred short years the basic outlines of the nervous system have been articulated. The biochemical, physiological, pharmacological, and structural features of the vertebrate brain have been described and in many instances defined. So too have the basic perceptual, emotional, mnemonic, attentional, and cognitive functions. In the past 20 years these fundamentals have accelerated at an exponential rate, leaving the field of brain and cognitive science swamped with riches of information. As we stand poised for the Century of the Brain, never mind the Decade of the Brain, our aspirations have expanded, our know-how has been refined, and our will to tackle the central mysteries of mind/brain relationships has been energized. Five years after the first edition of The Cognitive Neurosciences was published, another Summer Institute convened in Squaw Valley to produce its successor: this book. Once again the distinguished section editors led their handpicked colleagues through the maze of new data on the brain and mind.