This second edition is thoroughly updated to incorporate insights and issues that have come to the fore from the explosion of research in the past twenty-five years in all of the areas covered by the book. It includes an expanded bibliography and index, and adds new exercises for student application and class discussion. Its approach remains broadly based however, in order to accommodate a range of areas and data rather than focusing narrowly on one single theory or research area, and it continues to emphasize implications for language teaching, translation, and other practical applications.