This volume is the third edition of a book which is historically interesting as having been the first one published in France on the subject of psycho-analysis, in 1914. At that time Professor Hesnard was more adversely critical of the science than his senior colleague, Professor Régis, who has unfortunately died since. More mature reflection and personal experience have now convinced Professor Hesnard that many of his objections were invalid, and were merely signs of the general unconscious resistance. In this edition he makes an amende honorable. He has advanced