Not only a man's ideas, but also his ways of expressing them, have a strong persistence over time, so it is possible for the statisticians to determine disputed authorship by the pattern of words and the structure of sentences. I (author) have rewritten the present edition almost completely, but I have no doubt that it is the same book, and by only a slightly different author. Its distinguishing feature continues to be its concentration upon the traditional central core of economic theory--the theory of value.