I would like to acknowledge primarily the help, support and encouragement of my mother, Florence Clark Lawrence. Also John Carnes played an important role in making it possible for me to devote large amounts of time to it without going broke.

     Throughout most of the book I have used the masculine gender for personal nouns and pronouns. Please understand that "he" and "his" are meant to stand for "he or she" and "his or hers." All the typing and word processing was done by the author who is not a very good typist so please excuse this shortcut and interpret the wording accordingly.