First published in 1999. Routledge is an imprint of Taylor & Francis, an informa company.

This is Volume XII of nineteen in a collection of Abnormal and Clinical Psychology. Originally published in 1925, this research stemmed from many discussions about the applicability of psychoanalytic principles to manic-depressive insanity, whether the symptoms could be traced to unconscious mental processes in the same way as Jung had demonstrated it to be possible in dementia praecox and ended up with the general objective moving from that of psychopathological to one of psychological conclusions .