1. Minor changes have been made to correct typesetters errors, and to ensure consistent spelling and punctuation in this etext; otherwise, every effort has been made to remain true to the original book. 2. The chapter summaries in this text were originally published as banners in the page headers, and have been moved to beginning of the chapter for the reader's convenience. 3. Footnote G has been changed to refer the reader to page 164, to correct a typesetter's error.